The way FriendFeed handles Pownce entries. I caught a tweet in FriendFeed that Jeremy Brooks cross-posted to Pownce. Note that there is a URL in the tweet. In the Twitter tweet, the text is plain, and the link is clickable. In the Pownce post, the entire text is clickable, but links back to the Pownce entry on Jeremy’s Pownce profile. So to visit the corresponding link takes two clicks: once to Pownce, and another to get to the website.
It’s not a dealbreaker, but I keep looking for reasons to use Pownce, and all I ever see anymore are reasons not to.