The value of networks: mining and building

The value of networks or graphs underlies many of the internet (and for that read global corporate) giants.  Two of the biggest: Google and Facebook harness this in very different ways — mining and building.

Years ago, when I was part of the startup aQtive, we found there was no effective understanding of internet marketing, and so had to create our own.  Part of this we called ‘market ecology‘.  This basically involved mapping out the relationships of influence between different kinds of people within some domain, and then designing families of products that exploited that structure.

The networks we were looking at were about human relationships: for example teachers who teach children, who have other children as friends and siblings, and who go home to parents.  Effectively we were into (too) early social networking1!

The first element of this was about mining — exploiting the existing network of relationships.

However in our early white papers on the topic, we also noted that the power of internet products was that it was also possible to create new relationships, for example, adding ‘share’ links.  That is building the graph.

The two are not distinct, if one is not able to exploit new relationships within a product it will die, and the mining of existing networks can establish new links (e.g. Twitter suggesting who to follow).  Furthermore, creating of links is rarely ex nihilo, an email ‘share’ link uses an existing relationships (contact in address book), but brings it into a potentially different domain (e.g. bookmarking a web page).

It is interesting to see Google and Facebook against this backdrop.  Their core strengths are in different domains (web information and social relationships), but moreover they focus differently on mining and building.

Google is, par excellence, about mining graphs (the web).  While it has been augmented and modified over the years, the link structure used in PageRank is what made Google great.  Google also mine tacit relationships, for example the use of word collocation to understand concepts and relationships, so in a sense build from what they mine.

Facebook’s power, in contrast, is in the way it is building the social graph as hundreds of millions of people tell it about their own social relationships.  As noted, this is not ex nihilo, the social relationships exist in the real word, but Facebook captures them digitally.  Of course, then Facebook mines this graph in order to derive revenue form advertisements, and (although people debate this) attempt to improve the user experience by ranking posts.

Perhaps the greatest power comes in marrying the two.   Amazon does this to great effect within the world of books and products.

As well as a long-standing academic interest, these issues are particularly germane to my research at Talis where the Education Graph is a core element.  However, they apply equally whether the core network is kite surfers, chess or bio-technology.

Between the two it is probably building that is ultimately most critical.  When one has a graph or network it is possible to find ways to exploit it, but without the network there is nothing to mine. Page and Brin knew this in the early days of their pre-Google project at Stanford, and a major effort was focused on simply gathering the crawl of the web on which they built their algorithms2.  Now Google is aware that, in principle, others can exploit the open resources on which much of its business depends; its strength lies in its intellectual capital. In contrast, with a few geographical exceptions, Facebook is the social graph, far more defensible as Google has discovered as it struggles with Google Plus.

  1. See our retrospective about vfridge  at  last year’s HCI conference and our original web sharer vision.[back]
  2. See the description of this in “In The Plex: How Google Thinks, Works and Shapes Our Lives“.[back]

Six weeks on the road

I’ve been at home for the last week after six weeks travelling around the UK and elsewhere.  I’ve not kept up while on the road so doing a retrospective post on it all and need to try to catch on other half written posts.

As well as time at Talis offices in B’ham and at Lancs (including exam board week), travels have taken me to Pisa for a workshop on ‘Supportive User Interfaces’, to Koblenz for Web Science conference giving a talk on embodiment issues and a poster on web-scale reasoning , to Newcastle for British HCI conference doing a talk on fridge, to Nottingham to give a talk on extended episodic experience, and back to Lancs for a session on creativity! Why can’t I be like sensible folks and talk on one topic!

Supportive User Interfaces

Monday 13th June I attended a workshop in Pisa on “Supportive User Interfaces“, which includes interfaces that adapt in various ways to users.  The majority of people there were involved in various forms of model-based user interfaces in which various models of the task, application and interaction are used to generate user interfaces on the fly. W3C have had a previous group in this area; Dave Raggett from w3c was at the workshop and it sounds like there will be a new working group soon.  This clearly has strong links to various forms of ‘meta-level’ representations of data, tasks, etc..  My own contribution started the day, framing the area, focusing partly on reasons for having more ‘meta-level’ interfaces including social empowerment, and partly on the principles/techniques that need to be considered at a human level.

Also on Monday was a meeting of IFIP Working Group 2.7/13.4. IFIP is the UNESCO founded pan-national agency that national computer societies such as as the BCS in the UK and ACM and IEEE Computer in the US belong to.  Working Group 2.7/13.4 is focused on the engineering of user interfaces.  I had been actively involved in the past, but have had many years’ lapse.  However, this seemed a good thing to re-engage with with my new Talis hat on!

SUI: paper:

Web Science Conference in Koblenz

Jaime Teevan from Microsoft gave the opening keynote at WebSci 2011.  I know her from her earlier work on personal information management, but her recent work and keynote was about work on analysing and visualising changes in web pages.  Web page changes are also analysed alongside users re-visitation patterns; by looking at the frequency of re-visitation Jaime and her colleagues are able to identify the parts of pages that change with similar frequency, helping them, inter alia, to improve search ranking.

Had many great conversations, some with people I know previously (e.g. the Southampton folks), but also new, including the group at Troy that do lots of work with  I was particularly interested in some work using content matching to look for links between otherwise unlinked (or only partly inter-linked) datasets.  Also lots of good presentations including one on trust prediction and a fantastic talk by Mark Bernstein from Eastgate, which he delivered in blank verse!

My own contribution included the poster that Dave@Talis prepared, which was on the web-scale spreading activation work in collaboration with Univ. Athens.  Quite a niche area in a multi-disciplinary conference, so didn’t elicit quite the interest of the social networking posters, but did lead to a small number of in depth discussions.

In addition I gave talk on the more cognitive/philosophical issues when we start to use the web as an external extension to / replacement of memory, including its impact on education.  Got some good feedback from this.

Closing keynote was from Barry Wellman, the guy who started social network analysis way before they were on computers.  At one point he challenged the Dunbar number1. I wondered whether this was due to cognitive extension with address books etc., but he didn’t seem to think so; there is evidence that some large circles predate web (although maybe not physical address books).  Made me wonder about itinerant tradesmen, tinkers, etc., even with no prostheses. Maybe the numbers sort of apply to any single content, but are repeated for each new context?

WebSci papers:

The HCI Conference – Newcastle

I attended the British HCI conference in Newcastle. This was the 25th conference, and as my very first academic paper in computing2 was at the first BHCI in 1984, I was pleased to be there at this anniversary.  The paper I was presenting was a retrospective on vfridge, a social networking site dating back to 1999/2000, it seemed an historic occasion!

As is always the case presentations were all interesting. Strictly BHCI is a ‘second tier’ conference compared with CHI, but why is it that the papers are always more interesting, that I learn more?  It is likely that a fair number of papers were CHI rejects, so it should be the other way round – is it that selectivity and ‘quality’ inevitably become conservative and boring?

Gregory Abowd gave the closing keynote. It was great to see Gregory again, we meet too rarely.  The main focus of his keynote was on three aspects of research: novelty, value and reliability and how his own work had moved within this space over the years.  In particular having two autistic sons has led him in directions he would never have considered, and this immediately valuable work has also created highly novel research. Novelty and value can coexist.

Gregory also reflected on the BHCI conference as it was his early academic ‘home’ when he did his PhD and postdoctoral here in the late 1980’s.  He thought that it could be rather than, as with many conferences, a second best to getting a CHI paper, instead a place for (not getting the quote quite perfect) “papers that should get into CHI”, by which he meant a proving ground for new ideas that would then go on to be in CHI.

Alan at conference dinnerHowever I initially read the quote differently. BHCI always had a broader concept of HCI compare with CHI’s quite limited scope. That is BHCI as a place that points the way for the future of HCI, just as it was the early nurturing place of MobileHCI.  However CHI has now become much broader in it’s own conception, so maybe this is no longer necessary. Indeed at the althci session the organisers said that their only complaint was that the papers were not ‘alt’ enough – that maybe ‘alt’ had become mainstream. This prompted Russell Beale to suggest that maybe althci should now be real science such as replication!

Gregory also noted the power of the conference as a meeting ground. It has always been proud of the breadth of international attendance, but perhaps it is UK saturation that should be it’s real measure of success.  Of course the conference agenda has become so full and international travel so much cheaper than it was, so there is a tendency to  go to the more topic specific international conferences and neglect the UK scene.  This is compounded by the relative dearth of small UK day workshops that used to be so useful in nurturing new researchers.

Tom at conference dinnerI feel a little guilty here as this was the first BHCI I had been to since it was in Lancaster in 2007 … as Tom McEwan pointed out I always apologise but never come! However, to be fair I have also only been twice to CHI in the last 10 years, and then when it was in Vienna and Florence. I have just felt too busy, so avoiding conferences that I did not absolutely have to attend.

In response to Gregory’s comments, someone, maybe Tom, mentioned that in days of metrics-based research assessment there was a tendency to submit one’s best work to those venues likely to achieve highest impact, hence the draw of CHI. However, I have hardly ever published in CHI and I think only once in TOCHI, yet, according to Microsoft Research, I am currently the most highly cited HCI researcher over the last 5 years … So you don’t have to publish in CHI to get impact!

And incidentally, the vfridge paper had NOT been submitted to CHI, but was specially written for BHCI as it seemed the fitting place to discuss a thoroughly British product 🙂

vfridge paper:

Nottingham MRL

I was at Mixed Reality Lab in Nottingham for Joel Fischer‘s PhD viva and while there did a seminar the afternoon on “extended episodic experience” based on Haliyana Khalid‘s PhD work and ideas that arose from it. Basically, whereas ‘user experience’ has become a big issue most of the work is focused on individual ‘experiences’ whereas much of life consists of ongoing series of experiences (episodes) which together make up the whole experience of interacting with a person or place, following a band, etc.

I had obviously not done a good enough job at wearing Joel down with difficult questions in the PhD viva in the morning as he was there in the afternoon to ask difficult questions back of his own 😉

Docfest – Digital Economy Summer School

The last major event was Docfest, which brought together the PhD students from the digital economy centres from around the country. Not sure of the exact count but just short of 150 participants I think. They come from a wide variety of backgrounds, business, design, computing, engineering, and many are mature students with years of professional experience behind them.

This looked like being a super event, unfortunately I was only able to attend for a day 🙁  However, I had a great evening at the welcome event talking with many of the students and even got to ride in Steve Forshaw‘s Sinclair C5!

My contribution to the event was running the first morning session on ‘creativity’. Surprise, surprise this started with a bad ideas session, but new for me too as the largest group I’ve run in the past has been around 30.  There were a number of local Highwire students acting as facilitators for the groups, so I had only to set them off and observe results :-). At the end of the morning I gave some the theoretical background to bad ideas as a method and in understanding (aspects of) creativity more widely.

Other speakers at the event included Jane Prophet, Chris Csikszentmihalyi and Chris Bonnington, so was sad to miss them; although I did get a fascinating chat with Jane over breakfast in the hotel hearing about her new projects on arts and neural imaging, and on how repetitious writing induces temporary psychosis … That is why the teachers give lines, to send the pupils bonkers!

  1. The idea that there are fundamental cognitive limits on social groups with different sized circles family~6, extended family~20, village~60, large village~200[back]
  2. I had published previously in agricultural engineering.[back]

Apache: pretty URLs and rewrite loops

[another techie post – a problem I had and can see that other people have had too]

It is common in various web frameworks to pass pretty much everything through a central script using Apache .htaccess file and mod_rewrite.  For example enabling permalinks in a WordPress blog generates an .htaccess file like this:

RewriteEngine On
RewriteBase /blog/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /blog/index.php [L]

I use similar patterns for various sites such as vfridge (see recent post “Phoenix rises“) and Snip!t.  For Snip!t however I was using not a local .htaccess file, but an AliasMatch in httpd.conf, which meant I needed to ask Fiona every time I needed to do a change (as I can never remember the root passwords!).  It seemed easier (even if slightly less efficient) to move this to a local .htaccess file:

RewriteEngine On
RewriteBase /
RewriteRule ^(.*)$ code/top.php/$1 [L]

The intention is to map “/an/example?args” into “/code/top.php/an/example?args”.

Unfortunately this resulted in a “500 internal server error” page and in the Apache error log messages saying there were too many internal redirects.  This seems to be a common problem reported in forums (see here, here and here).  The reason for this is that .htaccess files are encountered very late in Apache’s processing and so anything rewritten by the rules gets thrown back into Apache’s processing almost as if they were a fresh request.  While the “[L]”(last)  flags says “don’t execute any more rules”, this means “no more rules on this pass”, but when Apache gets back to the .htaccess in the fresh round the rule gets encountered again and again leading to an infinite loop “/code/top/php/code/top.php/…/code/top.php/an/example?args”.

Happily, mod_rewrite thought of this and there is an additional “[NS]” (nosubreq) flag that says “only use this rule on the first pass”.  The mod_rewrite documentation for RewriteRule in Apache 1.3, 2.0 and 2.3 says:

Use the following rule for your decision: whenever you prefix some URLs with CGI-scripts to force them to be processed by the CGI-script, the chance is high that you will run into problems (or even overhead) on sub-requests. In these cases, use this flag.

I duly added the flag:

RewriteRule ^(.*)$ code/top.php/$1 [L,NS]

This should work, but doesn’t.  I’m not sure why except that the Apache 2.2 documentation for NS|nosubreq reads:


Use of the [NS] flag prevents the rule from being used on subrequests. For example, a page which is included using an SSI (Server Side Include) is a subrequest, and you may want to avoid rewrites happening on those subrequests.

Images, javascript files, or css files, loaded as part of an HTML page, are not subrequests – the browser requests them as separate HTTP requests.

This is identical to the documentation for 1.3, 2.0 and 2.3 except that quote about “URLs with CGI-scripts” is singularly missing.  I can’t find anything that says so, but my guess is that there was some bug (feature?) introduced 2.2 that is being fixed in 2.3.

WordPress is immune from the infinite loop as the directive “RewriteCond %{REQUEST_FILENAME} !-f” says “if the file exists use that without rewriting”.  As “index.php” is a file, the rule does not rewrite a second time.  However, the layout of my files meant that I sometimes have an actual file in the pseudo location (e.g. /an/example really exists).  I could have reorganised the complete directory structure … but then I would have been still fixing all the broken links now!

Instead I simply added an explicit “please don’t rewrite my top.php script” condition:

RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_URI}  !^/code/top.php/.*
RewriteRule ^(.*)$ code/top.php/$1 [L,NS]

I suspect that this will be unnecessary when Apache upgrades to 2.3, but for now … it works 🙂

Phoenix rises – vfridge online again

vfridge is back!

I mentioned ‘Project Phoenix’ in my last previous post, and this was it – getting vfridge up and running again.

Ten years ago I was part of a company aQtive1 with Russell Beale, Andy Wood and others.  Just before it folded in the aftermath of the crash, aQtive spawned a small spin-off  The virtual fridge was a social networking web site before the term existed, and while vfridge the company went the way of most dot.coms, for some time after I kept the vfridge web site running on Fiona’s servers until it gradually ‘decayed’ partly due to Javascript/DOM changes and partly due to Java’s interactions with mysql becoming unstable (note very, very old Java code!).  But it is now back online 🙂

The core idea of vfridge is placing small notes, photos and ‘magnets’ in a shareable web area that can be moved around and arranged like you might with notes held by magnets to a fridge door.

Underlying vfridge was what we called the websharer vision, which looked towards a web of user-generated content.  Now this is passé, but at the time  was directly counter to accepted wisdom and looking back seem prescient – remember this was written in 1999:

Although everyone isn’t a web developer, it is likely that soon everyone will become an Internet communicator — email, PC-voice-comms, bulletin boards, etc. For some this will be via a PC, for others using a web-phone, set-top box or Internet-enabled games console.

The web/Internet is not just a medium for publishing, but a potential shared place.

Everyone may be a web sharer — not a publisher of formal public ‘content’, but personal or semi-private sharing of informal ‘bits and pieces’ with family, friends, local community and virtual communities such as fan clubs.

This is not just a future for the cognoscenti, but for anyone who chats in the pub or wants to show granny in Scunthorpe the baby’s first photos.

Just over a year ago I thought it would be good to write a retrospective about vfridge in the light of the social networking revolution.  We did a poster “Designing a virtual fridge” about vfridge years ago at a Computers and Fun workshop, but have never written at length abut its design and development.  In particular it would be good to analyse the reasons, technical, social and commercial, why it did not ‘take off’ the time.  However, it is hard to do write about it without good screen shots, and could I find any? (Although now I have)  So I thought it would be good to revive it and now you can try it out again. I started with a few days effort last year at Christmas and Easter time (leisure activity), but now over the last week have at last used the fact that I have half my time unpaid and so free for my own activities … and it is done 🙂

The original vfridge was implemented using Java Servlets, but I have rebuilt it in PHP.  While the original development took over a year (starting down in Coornwall while on holiday watching the solar eclipse), this re-build took about 10 days effort, although of course with no design decisions needed.  The reason it took so much development back then is one of the things I want to consider when I write the retrospective.

As far as possible the actual behaviour and design is exactly as it was back in 2000 … and yes it does feel clunky, with lots of refreshing (remember no AJAX or web2.0 in those days) and of course loads of frames!  In fact there is a little cleverness that allowed some client-end processing pre-AJAX2.    Also the new implementation uses the same templates as the original one, although the expansion engine had to be rewritten in PHP.  In fact this template engine was one of our most re-used bits of Java code, although now of course many alternatives.  Maybe I will return to a discussion of that in another post.

I have even resurrected the old mobile interface.  Yes there were WAP phones even in 2000, albeit with tiny green and black screens.  I still recall the excitement I felt the first time I entered a note on the phone and saw it appear on a web page 🙂  However, this was one place I had to extensively edit the page templates as nothing seems to process WML anymore, so the WML had to be converted to plain-text-ish HTML, as close as possible to those old phones!  Looks rather odd on the iPhone :-/

So, if you were one of those who had an account back in 2000 (Panos Markopoulos used it to share his baby photos 🙂 ), then everything is still there just as you left it!

If not, then you can register now and play.

  1. The old aQtive website is still viewable at, but don’t try to install onCue, it was developed in the days of Windows NT.[back]
  2. One trick used the fact that you can get Javascript to pre-load images.  When the front-end Javascript code wanted to send information back to the server it preloaded an image URL that was really just to activate a back-end script.  The frames  used a change-propagation system, so that only those frames that were dependent on particular user actions were refreshed.  All of this is preserved in the current system, peek at the Javascript on the pages.    Maybe I’ll write about the details of these another time.[back]