IT contractors are likely to see a big increase in the number of firms incorporating social networking into their marketing systems in the coming months.

According to study by IT research firm Gartner, sites such as Facebook and Twitter are shaping the way consumers buy products.

The majority of buyers use social networks as a guide on what brands are worth buying and they then pass this information on throughout their own personal network.

"Companies attempting to use social networks should develop relationships with key customers over a period of time and progressively refine the social network profiles of those individuals," said Nick Ingelbrecht, research director at Gartner.

This is a tactic that smaller companies have used with their best customers for years, sure that they will pass on good experiences to friends and associates, he adds.

Earlier this year, Gartner predicted that by 2014, social media will replace email as the main source of interpersonal communication for 20 per cent of employees.