Maybe I'm missing some secret to twitter or something...but if you think someone is tweeting annoying or useless stuff, couldn't you just unfollow them?
Facebook has done more to alleviate this problem than Twitter with the default newsfeed being an algorithmically curated one (Top News) rather than the full firehose (Most Recent) and their hide functionality. I've always found hiding on Facebook could be more useful. Hiding a single update feels pointless. Hiding everything from a friend is rarely required. All that leaves is hiding an app, assuming their update came from one. That's where content-based filtering tools like http://slipstre.am/ (disclosure: my app) and http://proxlet.com/ excel, even though they're Twitter-only.