When people start downloading the Home software upon its April 12 release in the U.S., Facebook will become the new hub of their Android smartphones.
Switch on your phone and you'll see friends' photos, overlaid by status updates, links and eventually, advertisements in Facebook's quest to bring in more revenue and restore its stock price to where it stood when the company went public nearly 11 months ago.
About 80 percent of what currently appears within a Facebook user's News Feed will automatically be transferred into the "cover feed" of the Home service. For instance, a sibling's status update might be featured prominently on the phone's home screen when it's unlocked. Swipe a finger and there might be a photo posted by one of your best friends. Want to like what you see? Just tap on the home screen twice. Comments can be posted directly from the home screen, too.
If other friends happen to send you a message, their Facebook photo will pop up as a notification.
Other Facebook features, such as video, will be added to Home in future months. A Home version for Android-powered tablet computers also will be coming later this year.
Once they have had their fill of what Facebook is feeding them on the Home service, users can just swipe a finger on the screen to get to all the standard Android apps to listen to music, watch videos or send email.
At first, Home will only work on some Android devices, including HTC Corp.'s One X and One X Plus and Samsung Electronics Co.'s Galaxy S III and Galaxy Note 2. For now, Home isn't compatible with the Nexus phone designed by Google, a fierce Facebook rival whose pliable Android software is being modified to accommodate the new service.
A phone from HTC that comes pre-loaded with Home will be available starting April 12, with AT&T Inc. as the carrier. The HTC First will sell for $99.99 with a two-year data plan from AT&T.
Home is debuting after several years of speculation that Facebook intended to make its own phone or mobile operating system to drive more traffic to its social network. Facebook CEO Mark Zuckerberg said the speculation never made sense to him because he believes a company-produced phone might only end up in the hands of 10 million to 20 million people. The Home service gives Facebook a chance to take control of the main screen of every phone running on Android, the leading mobile operating system. In the U.S. alone, about 64 million people will be relying on Android-driven phones this year, estimated the research firm eMarketer.
"Just building a phone isn't enough for Facebook," Zuckerberg said Thursday during Home's unveiling at the company's Menlo Park, Calif., headquarters.
The idea behind the software is to bring Facebook content right to users' home screens, rather than requiring them to check various apps to see what their friends are up to, or to chat. Down the line, Facebook will integrate its existing camera app and other features. Though cameras and calls won't be built into the initial version of Home, Zuckerberg promised the software will be updated at least once a month to add more features and fix bugs.
"Home" comes amid rapid growth in the number of people who access Facebook from phones and tablet computers. Of the social network's 1.06 billion monthly users, 680 million log in using a mobile gadget. As a result, the money Facebook makes from mobile advertising is also growing. Taking over the entire screen of smartphones and, eventually, tablet computers will provide Facebook for a larger canvas for selling mobile ads.
Zuckerberg, already a multibillionaire, didn't dwell on Home's moneymaking potential Thursday. Instead, he depicted the software as a noble attempt to put a higher priority on personal relationships than utilitarian apps.
"Why do we need to go into all the apps in the first place to see what is going on with the people we care about," he asked.
"We think this is the best version of Facebook there is," he said.
That statement implies that using Facebook on Apple's iPhone and other smartphones may become a less enriching experience. Apple Inc., which rigidly controls how apps work on the operating system built for the iPhone and iPad, has ingrained more Facebook features into the most recent versions of its mobile software
Apple had no immediate comment about Home.
Zuckerberg said users can have an experience on Android phones unavailable on other platforms because Google makes the software available on an open-source basis. That allows phone manufacturers and software developers to adapt it to their needs.
Recognizing that text messaging is one of the most important tasks on a mobile phone, Facebook programmed Home to include a feature called "chat heads." This lets users communicate with their friends directly from their home screens — without opening a separate app.
"What Facebook wants is to put itself at the front of the Android user experience for as many Facebook users as possible and make Facebook more elemental to their customers' experience," said Forrester analyst Charles Golvin.
While the Home service probably makes sense for Facebook, Forrester Research analyst Charles Golvin thinks the company is overestimating "the extent to which this is something their users want."
"I'm sure there are people out there whose lives revolve around their social network and for them it makes sense to have it front and center," Golvin said. "But this doesn't describe the majority of consumers."
Google Inc. is among the companies hoping that Golvin is correct. The Internet search leader gives away its Android software for free, in the hope that it will steer phone users to ads sold by Google. With Home, Facebook will be muscling its way in between Android users and Google, creating an opportunity for Facebook to seize the advertising advantage.
This is not the first time a big Internet company has co-opted Android: Amazon.com's Kindle Fire tablets run a version of Android that strips out all Google services, replacing them with Amazon's equivalents. Google responded by releasing its own tablet to compete against the Kindle Fire last year.
The mobile advertising market is growing quickly, thanks in large part to Facebook and Twitter, which also entered the space in 2012. EMarketer expects U.S. mobile ad spending to grow 77 percent this year to $7.29 billion, from $4.11 billion last year.
Facebook, meanwhile, is expected to reel in $1.53 billion in worldwide mobile ad revenue this year according to eMarketer, up from $470.7 million last year.
Facebook's stock rose 82 cents, or 3.1 percent, to close Thursday at $27.07. That's 29 percent below its initial public offering price of $38. Meanwhile, the Standard & Poor's 500 index has surged by 20 percent since Facebook's rocky debut.
Barbara Ortutay reported from New York. AP Technology Writer Peter Svensson contributed to this story from New York.