The wires are abuzz with stories of Twitter and Facebook customers being robbed. It's fairly simple; you Tweet or tell your Facebook friends that you're going on holiday and a thief reads it; they break into your house, knowing full well you're away, and you lose a load of stuff. Insurance companies are starting to take this seriously and are looking at charging more to insure social media users.
This is of course plum crazy and will be unenforceable. They'll need to establish that your use of social media is actually irresponsible - they're talking about asking whether there are young people living in a house, for example. There will be outrage, it won't happen.
There are some simple precautions people can take. For example, don't announce holiday plans when you don't know who's going to be listening. Better still, be sneaky like me. I went away a few weeks back; I took the iPhone with me and sent a few 'reply' Tweets to innocuous messages - nothing in which I was going to become particularly engrossed, but enough to give anyone watching the account the idea that I was at my desk typing.
Social media can be used to put potential burglars off as well as encouraging them!