Offerpal works with advertisers to provide incentives - in the form of virtual money - to people to buy at their sites, use coupons, complete market research surveys subscribe to magazines and watch videos. It has also teamed with Plastic Jungle to let users convert unused and partially redeemed gift cards into virtual currencies.

Previously the Offerpal offers were available within games but the firm has now set up its own GamePoints portal, providing a central point from where gamers can find places to earn and spend currency.

During its beta launch 'Game Points' can only be spent in gaming applications on Facebook but other social networking sites such as MySpace, Bebo, Hi5 as well as standalone NMMO and virtual world sites will be added over time, covering more than 1500 games and apps.

George Garrick, CEO, Offerpal Media, says: "We launched GamePoints.com to empower online gamers with ways to earn virtual currency for free rather than having to pay for it, and to give them the choice of spending that currency wherever they'd like within our vast network."

The move to establish a universal virtual currency pits Offerpal against Facebook itself. The site has been testing its virtual currency system, Facebook Credits, with a small number of games and applications for the last few months ahead of an anticipated roll out this summer as it looks to take advantage of the potentially lucrative micro-payments market.