Google has lost its second high-profile employee to Facebook in less than a month.

Ethan Beard has quit as head of social media at Google to join Facebook as director of business development.

Sheryl Sandberg, who was Google's vice president of global online sales and operations, left on 4 March to become chief operating officer at Facebook.

Prior to Google, Beard served as director of business development at Viacom's MTV/VH1 unit, and helped to start the Big Internet Group.

Google did not seem particularly phased by the move. "While Ethan will be missed, we have the internal expertise to execute on our goals," said a spokesman.

Facebook has become one of the fastest growing social networking sites in the world, and is now valued at around $15bn.