Facebook has apparently hit 1 billion users. “There is on the order of 1,000 engineers and now on the order of a billion users, so each engineer is responsible for a million users,” Facebook CEO Mark Zuckerberg told Bloomberg Businessweek in an interview, adding that the milestone was “humbling.” That milestone is also challenging from a data-crunching perspective. “Doing data analytics at this scale is a big challenge, and one of the things you have to do is sample,” he said, explaining why his engineers and analysts couldn’t pinpoint the actual billionth user to sign up for the social network. “It’s like you’re not going to try to pull a billion rows from a database, so you’ll pull a sample and project out. I don’t even know if we knew who the billionth person was.” Zuckerberg also hinted at Facebook’s intentions with its user base: “The bigger question is, what services can get built now that every company can assume they can get access to know who everyone’s friends are.” Terming that development “transformative,” he suggested that degree of networking could drive “a big push in commerce.” Friend requests and content constitute “trillions of connections,” he added, which could eventually translate into “a better map of how you navigate the Web than the traditional link structure of the Web.” While he demurs at that point from outright saying Facebook will create some sort of search engine, he tilts enough in that direction—“I think there’s an opportunity to really build something interesting there”—to potentially keep some Google executives awake at night. He proved much more forthright about Facebook’s plans in the mobile-device space: “A lot of it over the next few years is going to come down to mobile. There is this funnel that I think is pretty clear and in our favor, which is there are going to be more people using mobile devices.” However, the social network needs to figure out how to monetize those mobile users. Despite that billion-user base, Facebook could find itself threatened by a next-generation social startup in the same way it steamrolled MySpace and Friendster back in the day. At least, that’s the belief of a recent joint survey by IDC and Appcelerator of 5,526 developers, 66 percent of whom believed that a “mobile-first social startup” could break Facebook’s hold on the social-networking market. And even as Facebook moves to more aggressively monetize its user base, it faces continual privacy-rights challenges from groups like the Center for Digital Democracy (CDD) and the Electronic Privacy Information Center (EPIC), both of which recently petitioned the Federal Trade Commission (FTC) to examine the alliance between Facebook and Datalogix, which have teamed up to measure the effects of marketing campaigns using Facebook data. So Facebook has indeed passed a significant milestone with one billion users. But it could run headfirst into some pretty big obstacles on its way to the second billion.   Image: Annette Shaff/Shutterstock.com