Personally, I think the whole industry of purchasing links and 'search engine optimization is sort of sleazy.
Google believes that a link which has been purchased or exchanged in a reciprocal manner should not benefit websites’ ranking in search results. Thus its “nofollow” rule calls on all website owners to use the “nofollow” tag when creating such links. According to mattcutts.com (a blog created by the head of the Google “webspam team”), any website which doesn’t use the tag for a link of this type may be penalized. Some have speculated that the recent reductions in PageRank values for many websites were caused by violations of this rule.
This has created controversy and complicated the process of buying or exchanging a link.
[From Google’s “Nofollow” Rule | Search Engine Optimization SEO Blog]
I think MT uses the “nofollow” tag, or at least makes it a user selectable preference, and I hope it uses it.
This isn't Greek to me. I know some Greek. I don't understand any of the techbabble. I marked it for del.icio.us. It looks important and I can ask the local genius for an explanation or go ask Google.