Word of mouth has always been a key method of publicising small businesses. But until now, the system hasn't really been formalised, with firms having to rely on luck as well as networking to get their name known.

However, a research firm and a marketing business have joined forces to to help clients find 'product evangelists', who'll do the talking-up for entrepreneurs.

The Keller Fay Group and ComBlu say they'll use the results to analyse just how effective word of mouth campaigns actually are.