IMHO it doesn't matter a jot what disembodied online personas say about me or anybody else.

I do believe a twit filter is useful if there are 1000s of posts that includes lots of off-topic stuff or boring interpersonal chat; without a filter the site's value can be effectively destroyed. Some services make it easier to filter OT posts, like profox, some sites break it into useful sections that you can switch off, like UT; and some allow you to filter prolific non-contributors or others whose calls you don't want to take for whatever reason.

I believe the objections around here are because some people use the twit facility as a taunt, relying on their target's sensitivity to score a passive-aggressive hit. But IMHO that says more about them than about their target whose best response is to ignore it.