I really, really like this apparent arms race between bitbucket and Github lately. It might just be observer bias, but both seem to have put in more and more features since bitbuckets big revamp (which imo made it actually usable).
This is a tad annoying when writing comments with indented code blocks, since it pops up with every `@` you write, which in Coffeescript or Ruby can happen frequently. Great, otherwise.