Which of the following was not an April Fool's Day prank by Google (Nasdaq: GOOG) yesterday?

  • Linking all of its YouTube featured videos to a clip of Rick Astley's "Never Gonna Give You Up."
  • Launching Virgle, a pairing of Virgin and Google to start populating Mars come 2014.
  • Rolling out a Custom Time feature for Gmail, to let you pre-date your email.
  • Offering a Wake Up Kit in Google Calendar, beaming progressively annoying text messages your way until you do, in fact, wake up.
  • Making Google Docs, the company's online word processor, available offline.

If you're stumped, the last one's actually the real deal. Google Docs, the Web-based word processing application that is part of the free Google Apps programs, now has limited offline functionality.

It may not seem like much of an upgrade, especially to those who are perpetually online. However, in "bringing the cloud with you," as Google describes it, it's even more of a threat to productivity application suites like Microsoft's (Nasdaq: MSFT) Office, Corel's (Nasdaq: CREL) WordPerfect, and Apple's (Nasdaq: AAPL) iWork. It also raises the stakes for fellow Web-based word processing programs like Sun Microsystems' (Nasdaq: JAVA) StarOffice and Adobe's (Nasdaq: ADBE) Buzzword.

Then again, why kid ourselves? Google partners with many of these companies. Microsoft -- the market leader in word-processing software -- is Google's primary target here. Even if Google Docs doesn't catch on (and that's always possible; it's been in the game for more than two years since its acquisition of Writely without making a dent in Mr. Softy's armor), it's enough of a move to raise the stakes.

It may also help lower prices. That's obviously the last thing Microsoft needs as it continues to lose money on MSN.com, and as Windows Vista adoption rates keep coming up lukewarm. Deep down inside, Microsoft has to be hoping that Virgle -- and not the offline availability of Google Docs -- was the legitimate new entry out of the Google camp this week.

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Longtime Fool contributor Rick Munarriz is a huge fan of Google, and it would be his homepage if it weren't for Fool.com taking up that piece of real estate. He does not own shares in any of the stocks in this story. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.