Me and thousands of other people, continue to use wordpress, one of the leading blog management systems (sounds kewl, eh? ;) ), and proof that is it in fact leading is here.
Apparently, Wordpress.com, has the least spam, compared to other free blog-hosting services. The honored list of competitors, include the likes of google, myspace and AOL, each one of them goliaths! Matt Mullenweg, the creator of Wordpress, associates the success of wordpress.com spam protection to Akismet. This is something that I use now. I used spam-karma before this, which was pretty good, but with Akismet, it is almost zero-management.
Google, with its wonderful, spam filter on gmail, should be able to do much better, but then, comment spam is a very different ball game.