When I was trying to find examples of comments or commenting systems to rate in order, I didn’t expect Facebook to appear where it was in the list. Indeed, if you go to set up a new account and change your name, there’s a strict warning about overusing punctuation and random capitalization. The page notes that your name change will not go through if it’s for vanity reasons, either. I think that goes a long way towards encouraging people to step up with a real identity.

It’s unfortunate that the wall comments on popular applications and groups are the lowest quality comments on the scale. It’s nearly impossible to go into a group and not see a severe warning from the administrator saying that the unneeded personal/racist attacks will not be tolerated.

One thing that goes a long way towards fostering an environment of on-topic, insightful discussion is active moderation and communication with the community. Nothing’s really going to replace responsible moderation by site staff members, but like you mention, on larger sites it’s impossible to do this. The ability on sites like Engadget, Digg, and now YouTube to allow down-voting and “mark as spam” for particular comments somewhat alleviates the drivel to sort through.

There are also some technical solutions that can and should be implemented. Since my personal site doesn’t have too much traffic, an installation of Akismet on top of WordPress deals with things nicely for now. If I got really ambitious, I’d start counting things like capitalization (or not enough capitalization); occurrence of numbers or exclamation marks in a post; and repetition of characters in a row. Posts like this could be flagged on a SpamAssassin-like scoring system, with comments above a certain threshold being flagged for moderators. (I assume there’s already an open source project for this somewhere out there though.)