According to the BBC, a tenant who used Twitter to complain about mould in her Chicago apartment is being sued by the lettings agency. Is it really libellous though? As someone quite rightly points out, should a humble tweet be deemed as a form of publishing? Or, is it merely the 'electronic version of a coffee shop, where you can gripe privately but have your gripes overheard?'Twitter is fleeting and disposable by its very nature. Does this mean that all our pronouncements will now have to be run by our legal departments? If I tweet that my train isn't running on time will I have to consider being sued by Virgin? Or risk the wrath of McDonalds if I say their mozzarella dippers turn my stomach? Tread carefully fellow Tweeters, indeed.