This is just ridiculous. If Facebook and Twitter cannot be mentioned on-air as it is 'advertising', then does that mean all brands should be edited out? What do you say if you want to take a drink a cup of tea out of your Thermos flask, throw your frisbee and play on your Playstation 3 before cleaning the room using a hoover?
Flask, flying disc (although I wasn't aware frisbee was a brand name), games console, and vacuum cleaner.
Remember that the BBC has rules about this too, although they aren't always strictly followed. Blue Peter famously had to refer to Sellotape as "sticky backed plastic", and there's the stock phrase "other brands are available".
Of your examples thermos and hoover are well genericised now anyway. The others it will depend on context.
How encompassing is the rule? Broadcasters often have their own twitter feeds that they mention on air - the whole point being that they are popular and thus a greater chance of something useful or interesteing being tweeted. Its no good quoting a site that viewers or listeners by and large havn't heard of. So is it just the verb to "tweet" or the noun "facebooker" that are banned? Other sites are obviously not different and/or innovative enough to warrent such gloabal reknown as facebook and twitter; the playing field isn't level so why should they all be treated equally?