Microsoft promised to make a "major" announcement on Monday that started the Internet buzzing with talk that it would involve taking on Apple iPad with tablets running on Windows software.
Speculation by technology news outlets ranged from Microsoft unveiling its own tablet computer to it beefing up online film, television or music offerings and using a partner's Windows-based tablet to demonstrate.
"This will be a major Microsoft announcement," the enigmatic invitation read. "You will not want to miss it."
The fact that the press event will be held at a yet-to-be disclosed venue in Los Angeles hinted heavily that entertainment industry content would be in the spotlight.
Microsoft might announce a deal to buy online video service Hulu and weave it into the Xbox Live online entertainment service linked to the Redmond, Washington-based company's leading Xbox 360 videogame consoles.
"It's in L.A., so they are going to talk about media," said independent Silicon Valley analyst Rob Enderle.
"It could be about hardware, but after the Kin failure and the Zune failure I can't picture the person at Microsoft who has the balls to pitch a Microsoft tablet."
Kin was a youth-oriented mobile phone from Microsoft that was pulled from the market after just weeks, while Zune was the longtime Apple rival's now-abandoned MP3 device that unsuccessfully challenged the iPod.
Enderle did expect some kind of hardware to be unveiled at the event, but thought it would most likely be related to Xbox or be made by partners -- with Samsung and Vizio high on the list of contenders.
News of the day could be an early release of Windows RT, the Microsoft operating system to power tablets or other mobile devices running on ARM chips, complete with gadget makers showing samples, according to the analyst.
"The lid on this event is extremely tight," Enderle said. "It clearly has a major hardware component to it."
Microsoft last week stepped up its quest to be at the heart of home entertainment by synching Xbox 360 videogame consoles to smartphones and tablets while adding more blockbuster content.
Microsoft introduced Xbox SmartGlass software for linking the consoles to iPhones, iPads, Android-powered gadgets and, of course, devices powered by the technology titan's new Windows 8 operating system.
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