Twitter and Facebook have both featured in court actions involving UK citizens recently.
Facebook because JoanneFraill, a British juror, used it to correspond with a defendant in an ongoing court case. The fact that it was done on Facebook is almost incidental and makes the news because it is the first reported time Facebook has been used by people conspiring to derail British justice, and threaten our jury system in this way.
Twitter's involvement with the British justice system has been more interesting. In the first instance, a British court asked Twitter to name the individuals who had broken the super injunction against Ryan Giggs. Twitter quietly ignored the request. Not unreasonably as its terms of service say "All claims, legal proceedings or litigation arising in connection with the Services will be brought solely in San Francisco County, California, and you consent to the jurisdiction of and venue in such courts and waive any objection as to inconvenient forum." Ryan Giggs could I suppose claim, if he doesn't tweet, that he had not agreed to these terms, but they seem a fairly big statement of Twitter's intent when it comes to court action. And there may have been another reason why Mr Giggs' lawyers advised against travelling to California.
Another court case did take place in California. South Tyneside council asked for the names of people behind Twitter accounts that they claimed had slandered their councillors and staff. I think that the basis of the court action was that the parties involved wanted to sue for slander and couldn't until they knew who to sue. So the US court instructed Twitter to hand over the names. Twitter as is its avowed intent, asked the potentially defending party if they wanted to contest the initial court action requesting their name. They declined, possibly on grounds of expense. (South Tyneside paid £250,000 to get the name in question so contesting would presumably have risked costing this and more.)
This seems a strong indicator of how US based social media companies will behave in future - working with US courts but ignoring others. This plays well for freedom of speech as the US courts value this more so than British courts. Ryan Giggs' lawyers could probably have got the names of the injunction breakers by going to the Californian court, but would have had to admitted in court that injunction breakers were correct to name him.
One unsurprising lesson to be learned from this is that social media companies are not going to protect your anonymity against all comers. So if you want to whistleblow but would prefer to be an anonymous hero rather than a named martyr, selective use of internet cafes, once only email accounts and short term Twitter accounts would seem sensible.