Facebook is starting to push ads into its mobile applications (emphasis added):
While Google has drawn criticism over how it collects personal data, it relies on more straightforward advertising than Facebook — running Internet-search ads or graphical commercials within applications, for instance. Facebook’s approach counts in part on its members promoting companies among their friends. Facebook members who “like” brands may not realize their preferences are used as the basis for advertising sent to other people.
“Our vision is that interaction on Facebook with a brand is as exciting as it is with family,” Chris Cox, vice president of product at Facebook, said last month at the company’s FMC conference for marketers in New York.