"Un-say." Vb. To retract (something said or written).

The ability to unsay something must be top of the wish list for most politicians. Just imagine a world of realtime self-editing, where your comments could be erased from the memory of an audience if the reaction wasn't positive or, and this is more likely, the comments themselves were ill-judged. How much do you think Gordon Brown would like to have unsaid his infamous bigot slur against poor old Mrs Duffy? Andrew Mitchell probably wishes he walked to work that day as much as he wishes he could untell a policeman to f**k off.

In the absence of such an ability, most people fall back on correcting themselves ("what I actually meant was...") or pleading over context ("It's important to remember X...)  or denying they said anything in the first place.

But there is a world in which "unsaying" something is as easy as pressing delete. You can float an opinion and if it turns out to be too controversial you can erase it. You can state a fact and if it turns out later to be wrong you can just get rid of it. I'm talking of course about Twitter; that extraordinary stream of consciousness, prejudices, passions, fights, rumours and debate. It's a remarkably dehumanising medium, and as well as emboldening its users in arguments, it allows for self-editing in a way that changes the nature of debate itself.

I should declare here that last week, I deleted a tweet. Someone asked me if I was sitting in a certain lecture that was, for a variety of reasons, generating a lot of buzz among journalists on Twitter. I replied "negative" - before realising that I was meant to be there and probably shouldn't have advertised my absence. So I deleted it. This, I would argue, is a fair act of self-editing. An unfair act (though hardly serious) would be to have answered "yes" only to be called out on the lie, and then to have deleted the tweet.

Politwoops is a highly addictive US site that gathers up all the Tweets posted by politicians which were subsequently deleted. It features the usual host of DM fails, where (in the style of Chris Huhne) a politician sends what they think is a private message to a journalist and accidentally send it as a public tweet. Congressional challenger Dick Muri (Republican) tweeted, then deleted: "No comment." We can also enjoy plenty of tweeted-then-deleted links to Republican victory parties that of course never happened. They never happened in reality because the Dems won, but removing evidence that you even had the thought is the next step in self-correction.

The most recent flurry of “tweleting” (my new word for deleting tweets) has been by those less than cautious tweeters who decided to climb aboard the passing McAlpine bandwagon. Of course, the deletions won’t save the more high profile offenders from libel action. 

The problem for most would-be tweleters is that the urge to erase a previous thought or position is normally only triggered by outrage or derision at its original appearance. Far better all round to just be a little less cavalier and not to assume that there is some kind of online safety in numbers. To tweet is to publish. The ease and speed with which spontaneous thoughts or knee-jerk reactions can be shared means that we think less before starting to type than we would before starting to speak. More than a few big names from the Twittersphere are finding this out to their cost.

In the meantime, I stand ready to delete this article if need be.