I'd be interested to hear what 'normal', non-power users of Twitter think. The 'mouth-breathing buffoons' that Jeff Rock so denigrates (and evidently make up most of Twitter's users) may actually like this UI feature. Viewing the world through nerd-tinted spectacles makes many things seem horrible that are perfectly OK to a regular person.
In 2011, people interested in NCAA basketball should see sports stuff. People interested in Ruby on Rails or Amazon EC2 should see IT stuff. It should be pretty easy to spot people's interests on Twitter.
Amazon.com doesn't recommend women's clothing to me. Netflix doesn't show me Spanish language movies.