spam going up

I noticed the size of my spam folder seemed to be going up.  16.5 Mb in the first 14 days of July.  I checked back to see what it was previously (I am truly sad and archive my Trash folders, so can see what t was!).  The 9 months October-June was 154 Mb, so with July at 33Mb in one month that looks like near doubling in rate.  Actually looking back the previous 19 month period was 88Mb, so again doubling.

I checked Eudora’s record of the numbers of emails arriving (right).  This incoming mail is  dominated by Spam and shows it going up from about 3000 a week in January to over 5000 a week now, again consonant with a doubling about every 9 months.  I’m not sure if this is because the server-side spam exclusion is letting more through or because the total volume is increasing. If the latter, the trend is worrying, not just for those of us personally trying to cope with the volume, but also for mail servers.

Moore’s law for disk capacity is about doubling in 18 months, and personally I’ve noticed that my actual document sizes tend to double about every 3 years (more media etc.), so basically disk space keeps ahead of disk need.  However, if the Spam volume is doubling every 9 months it is faster than disk size increases, so mail servers may find themselves struggling with the throughput, even if they can filter and remove it.

Is it just me or are other people seeing a similar pattern?