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Apple has updated its website with a mysterious teaser, indicating an "exciting announcement" is coming to the company's iTunes service on Tuesday. But what could it be?

Minutes after Apple switched the front page of its website to a giant announcement indicating a forthcoming launch, technology blogs buzzed with anticipation. The site now reveals that "tomorrow is just another day. That you'll never forget," but what exactly the company has planned remains up for debate.

Gizmodo asked for a network-accessible storage area for music files and more, so called "cloud storage" that would allow users to access their files from any computer anywhere, not just the five authorized PCs Apple currently limits you to.

As evidence, Gizmodo pointed to the iTunes Live trademark the company filed for back in May.

"It's also notable that the teaser appears to be showing up in the U.S. for now, despite Tokyo and London time being featured on clocks," the site wrote. "The plot thickens!"

Engadget was similar speculative, and similarly short on details: "All streaming subscription service based out of that North Carolina data center? More video content in the store? Apps for the Apple TV with the iOS 4.2 update? The Beatles?"

The fact that the company has replaced the entire front page of its website with the teaser leads bloggers at CrunchGear to speculate that the news will be big, noting that "for them to post a huge 'Guess what we’re doing!' on the front page is a big deal."

Meanwhile, PCMag.com noted that Apple updated the iTunes software to version 10.1 on Friday, in preparation for the launch of the new mobile software platform, iOS 4.2.

Apple did not immediately reply to requests for more information.