Weblog Database

I've noticed do follow blogs or blogs using comment luv or something similar get a ton of comments (after you wade through all the spam).



I am thinking of using this plugin and making the blog do follow. If let's say a comment is left on your site and it includes a link to their blog. Say down the road, the site changes and becomes a spam site or porn site, do you end up getting penalized for linking to a bad neighborhood?