
It may make sense to have a spam filter on your network/PC to block out spam sent using old-skool techniques. But for all the new spam-blocking systems that are updated every hour/day/week (delete as applicable), the spammers will always be one step ahead.
If the spammers weren't one step ahead at all times, the spam blockers would not know what to block, as the spam blockers would be thinking ahead of the spammers and would therefore be blocking things that may never become spam.
I read somewhere recently - if somewhere knows where, I'd love to bookmark it so I can argue successfully the benefits of having stupid email addresses - that people with email addresses starting with A, S, M or Z get 40% more spam than those people with email addresses starting with any other letters.
Maybe the solution is for webmail providers to note that people creating email addresses with the letters that are most likely to get spammed will get more spam than if they chose an email address starting with another address.