Continued from page 1

Facebook, which is based in Menlo Park, Calif., easily could offer sales of movies, music, even houses and cars. But believing it can expand into those markets requires a huge leap of faith, said Hudson Square Research analyst Daniel Ernst.

“It’s like saying because Chipotle has been good at selling burritos in certain urban markets in the U.S., it should be able to make more money selling Chinese food in France,” he said.

Facebook says roughly half its audience _ about 425 million people _ now gets access to its service on smartphones, tablet computers and other mobile devices. But the site acknowledges it hasn’t figured out the best way to make money from mobile users.

The application-driven systems on mobile devices pose another threat because they could allow Zynga and other services to offer their own mobile apps to bypass Facebook and connect directly with users.

The rise of mobile devices also opens up an opportunity for Google to expand the audience of Plus, its social networking alternative to Facebook. Although it hasn’t done so yet, Google could make Plus part of the Android operating system that runs 250 million smartphones and tablets.

Zuckerberg, Facebook’s controlling shareholder as well as its leader, is promising to put users’ interests ahead of the company’s financial interests.

“Simply put: We don’t build services to make money; we make money to build better services,” Zuckerberg wrote in a letter included in Wednesday’s IPO filing. “These days, I think more and more people want to use services from companies that believe in something beyond simply maximizing profits.”

___

AP Technology Writer Barbara Ortutay in New York contributed to this report.