Twitter is apparently prepared to give British investigators information about users accused of violating a "super injunction". The injunction prohibits anyone from talking about the involvement of Ryan Giggs, a soccer player, in an extramarital affair. That sentence I just wrote is probably illegal in England. As a protest against this injunction, people have been tweeting about Giggs by the thousands. It's been assumed that because Twitter is not based in the UK, nothing would come of this but Twitter now says it will provide information if it was "legally required" to do so.
What will be interesting here is what that information would be. Twitter is already a public place. So would user emails be forked over?