One of the few competitors to Twitter that had some traction, utterli (originally named Utterz), has a nasty weak point. You can’t easily stop following another user.
Typically one can Unfollow, a lá Twitter, directly from the user’s page as well as one’s list. On utterli, not so much.
Utterli make it very easy to follow others, as well as easy to follow anyone following you via a single ‘follow all’ action. This is a great feature.
It becomes a problem as spammers join in. This AM I needed to remove an MLM huckster. It wasn’t possible from the user’s profile page, from his update page, etc. Only from my following page, and I’m following a few hundred people.
It’s a note of success that they’d need this blocking.