Anyone who is in the business of on-line promotion and marketing will know just how import social community networks can be – and especially Twitter.com. Most important of all, however, is not simply the number of Tweets created, but the number of re-tweets…

A recent survey claimed that about 1.5% of all tweets are actually re-tweets and the chances are that this figure is set to increase. Many more people are becoming familiar with twitter and twitter culture and more tools are coming out for sites making it easier to re-tweet.

Soon enough, too, Twitter will incorporate the retweet feature on to Twitter.com, which means that the number of re-tweets will rise significantly.

But there is an art to Tweeting and re-tweeting that will help your business and product marketing along no end.

One of the queens of Tweeting is Shéa Bennett, who writes the blog Twittercism. She has come up with an equation re-Tweet optimisation: Twitter has a 140-character limit, so it’s vital that you consider your user name and how many characters you need to leave free. Bennett believes you should always  ensure that you leave a minimum of 12 to characters at the end of each tweet. If not, you are forcing those who want to retweet to edit your submissions so that they can give the proper credit. Because of this extra work, there are many times when they simply won’t bother retweeting you at all.

Whether you leave 15 characters at the end – or more – the key to creating successful retweets is to think about the usability for your readers. It’s a simple concept and one that you should aim to get right…