Did WordPress 1.5 have any spam filters

I ask because I never used any anti-spam plugins and didn’t have a problem with it on my teeny blog. I recently upgraded to WordPress 2.0.2 and now Askimet is claiming to catch 200+ comment (not trackback) spam a week.

I haven’t had any explosion in hits or anything so I don’t know how this happens. Is there some sort of comment-posting vulnerability in 2.0.2 that wasn’t in 1.5?