username in from address

[Mark Chaney]

Ever notice that a lot of spam seems to have your username in their from 
address? Such as an email sent TO b...@domain.com is FROM 
blah...@anotherdomain.com (notice 'blah' included in the from address). 
This appears to be the case with a large a majority of the spam that 
gets through my filters. Any ideas how to handle this? Would be nice to 
be able to add a score for matches like that.

Thanks,
Mark