Sometimes, I really appreciate slashdot. Yes, lots of trolls, lots of garbage, be afraid to read at -1, etc. But they don't edit or delete comments. The don't care what kind of language you use. I like that a lot in a weblog/forum type thing.
Fark has filters to change words... it can be amusing sometimes, and some of the language that would otherwise be used maybe isn't great for polite company, but really, what does it matter if someone says 'shit' on Fark. Fark's moderators also delete comments. Perhaps they only do so when said comments are garbage, but how do we know that? Not that the commentary on fark is generally worth much more than a cursory, humerous read, and then usually only when it gets into good stories, like the 'what will your last words be?' thread. That kind of thing can be great.
Of course, I haven't yet had a time when I felt I needed to delete a comment on this. I suppose I should install one of the anti-spam MT plugins, to help prevent that, but let me just say that I will only delete comments based on it being spam/absolute garbage. Simply being an unpopular opinion or an inflamatory comment isn't enough. Neither is a comment being totally off-topic. Although, perhaps a 'gallery of rogues' kind of place to put the junk that surely accumulates might not be a bad thing.
Certainly, if you run your own forum or weblog, or whatever, you have every right to restrict/edit comments and such, however you want. If you don't do that, you have the responsibility to deal with the crap that will undoubtedly flood your site. I just wish more places would do like Slashdot, even if it is a barren wasteland when read at -1. It bothers me that some places will delete comments out right, it bothers me more if they'll edit a user's comments. Even if it is done by the software.

Chris is a jerk.
(-1) Flaimbait
Thank you for not deleting my comment. Now watch my porn.
i use the MT anti-spam plug in...i guess it works. its more of a blacklist thing, but the UI is nice.
I've only deleted one comment from my blog and it was because the person didn't want to get fired if their boss read what they said. I feel it was a worthy exception...
Yeah. Comments left while making silly drunken comments about one's boss should probably be stricken from the record at the request of the poster.