The leading theory is that the company will unveil a video-chat feature powered by Skype.
Facebook didn't provide any details in an e-mail inviting media members to the event, to be held at its Palo Alto, California, （headquarters）. But CEO Mark Zuckerberg promised last week it would be "something awesome."
Zuckerberg was touring Facebook's engineering site in Seattle and wouldn't give many details, only saying that the announcement would be about something developed there.
It's hard to imagine the （timing） of the announcement is random.
Since it was launched last week, Google has been getting all the online buzz in the social-media world for its new networking platform, Google+.
Most popular Google+ user? It's Facebook's Zuckerberg
Google may be digital light years away from rivaling Facebook's nearly 600 million users worldwide. But after Buzz, Wave and other （failed efforts）, Google+ looks like the search engine's most serious leap yet into the social-networking world.
And that could mean, as competing （smartphone） makers discovered with Google's potent Android system, that Facebook has a real rival on its hands.
