The agency, which was founded in 2004, specializes in online fundraising and social networking, and has a roster of non-profits, political candidates and causes, while also doing work for corporate clients such as HBO, AT&T and National Geographic.
The shop is best known for Obama for America, the candidate's 2008 presidential campaign, which included an e-mail campaign that engaged more than 13.5 million supporters, and a program where supporters could earn game-style "points" that inspired them to become more deeply involved. The agency claims 130 employees and has grown more than 30% per year since its founding, according to an announcement.
WPP, meanwhile, owns some of the top advertising agencies in the world, including JWT, Ogilvy and Grey.