I saw the same blog activity this weekend that Kalsey writes about.
Basically, if you have a blog, and you get spammed, and you don't clean out your spam comments, it's kind of like weeds in a garden or those people who host virus/spam programs on their machines (either unwittingly or consciously.)
I don't want to give blog spammers any more link-juice than they already get, so I can't point to specific examples, but this is a problem that will get bigger.
New comment spam technique [kalsey.com]
I'm still not convinced that the main goal is to increase page rank so mauch as have lots of "portals" out there linking to you. For example, if I search for the famous "Rosaane Bar Nude video", the first few pages of results might be clearly porn sites, and since I'm a cheap pervert I skip over them, thinking that *someone* must have a free link to it. This would most likely be a blog right? So now I come to a blog page, and click on that, I get basically a link list of porn sites that host the video. It's a free portal for them.
I came to think of this because I saw some hits to my site from goolge for the "Paris Hilton sex video". They were going to a post that had some unnoticed spam. Now, the spammer *may* have gotten a higher page rank by being listed on my site, but more likely, they benefited because the person searching for the video came to my site, then followed the link to their site.
Just a thought.
I think what we all really want to know is why is Kevin searching for "Rosanne Bar Nude Video".
brrrrrr ;)