On the WordPress hackers list, as expected, there's a heated discussion about rel="nofollow". The trigger: Matt has built rel="nofollow" into WordPress. Part of it is a filter that could be easily disabled. But another part is hardcoded directly into the code (for example, every author link in comments is permanently tagged with rel="nofollow"). And Matt doesn't want to build in an option, but rather force everyone, so to speak, to implement this feature.
What really bothers me about the whole thing is the absurd reasoning. Sorry, but what happens to links in my system is something essential for me as a site operator — nobody tells me what to do there. Okay, fine, I can patch my software — but the attitude toward users on this point is pretty shitty.