As I write, Roger Federer, as defending champion, is playing the first match at this year's U.S. Open, in Flushing Meadow, New York.

The tennis professionals have got a new rule to abide by this year: they have been forbidden to twitter during matches. I'm serious.

Quite why, sending, for example, an expletive-laded tweet between first and second serves would give a player some advantage is beyond me, although perhaps Andy Murray - who is convinced he'll beat Federer in the final this year - would like to show off his virtuosity by twittering while he waits microseconds for the ball to come back over the net in a long rally.

I guess the rule is meant to prevent over eager coaches to provide "helpful" advice - or tell their guy to dump the set if there's money to be made from bookmakers. But it's probably counter-productive. Years ago, I remember reading an American football team was provided with 2 way radios so they coach could tell them what to do - and they lost by a record breaking margin.

Tweet, tweet - the ball's behind you.