I noticed our blog just crossed the 100,000 mark on bogus comments tossed into the trash by Akismet. Thanks, Automattic.
Akismet reports they're closing in on 8 billion (that's with a "b") spam comments thwarted webwide.
They indicate 87% of attempted blog comments are spam. That's lower than the email spam rate, I think, which is in the high 90s.
Akismet is best-known as a Wordpress plugin. It is also available for Movable Type, Drupal, Blojsom, Lifetype, and other platforms.