In a single day, Bing has increased the number of fans of their Facebook page by 500 percent. How? By using clever social media advertising embedded within the popular Facebook application Farmville.

The advert appeared yesterday inside the game Farmville, encouraging players to become a fan of Bing in exchange for free farm cash (the virtual currency used within Farmville). As an incentive for players to act, Bing positioned themselves as the ideal search engine to help them win the game with tips and solutions for how best to use their crops and animals. Probably the cleverest part of the promotion was the fact that users could fan the Bing page without interrupting their game.

As a follow up, Microsoft’s social media team then set about creating dedicated updates for Farmville users on the Bing Facebook page.

The Bing Facebook page started the day yesterday with around 100,000 fans and that figure is now well above 500,000.