Yahoo! has accused Facebook of usurping patents, especially concerning advertising and protection of private life. Facebook is claimed to have used ten patents without authorization. Yahoo! said: "The whole model of the Facebook social network, which permits users to create a profile and to create networks between them, are based on Yahoo!'s social network patent."

Facebook " We are disappointed that Yahoo!, a historic partner of Facebook and a company which widely benefited from our partnership, decided to turn to a legal action. We learnt this decision at the same time as the press, and we shall defend ourselves vigorously against this procedure which makes us perplexed."

Even if the conflicts of intellectual property are legitimate in the United States, this dispute arises at an inconvenient time for Facebook, which is currently preparing to go public.