April numbers are in from Web analytics firm Net Applications, and the song remains the same.

Microsoft (Nasdaq: MSFT) still owns the largest slice of the web browser market; 60% of all page requests tracked by Net Applications last month came from an IE browser. The open-source Firefox browser is holding steady in second place with a 24.6% market share, and Google (Nasdaq: GOOG) continues to pull away from Apple (Nasdaq: AAPL). Google's Chrome now holds a 6.7% share, versus Safari's 4.7% of the global market.

When comparing with last month's report, two clear trends emerge: Chrome is stealing market share rapidly, and mostly from Internet Explorer. Chrome increased its modest market share by 9.8% this month. If it keeps that pace up for a year, the once-irrelevant upstart would land a respectable 18.8% market share at the expense of all the other players.

Over the long term, Firefox and Chrome have been decimating Microsoft's IE -- and look likely to continue doing so. Microsoft's browser is still the default Web application on most computer systems shipped, and that's a huge advantage for Mr. Softy. But Google has already struck an accord with Sony (NYSE: SNE) to have Chrome as the default browser on some Sony Vaio laptops. That's a small deal in the grand scheme of things, but imagine what would happen if a market leader like Hewlett-Packard (NYSE: HPQ) signed a similar deal with Google, or the Firefox Foundation, or even Opera. Microsoft's browser colossus stands upon feet of clay, it seems.

And of course, the continuing shift of web browsing from old-school computers to fancy new smartphones will only magnify this trend. Chrome is the browser on Android phones like the HTC Incredible or Motorola (NYSE: MOT) Droid, and although at least one rival browser is available, Safari is probably what you'll use on an Apple iPhone or iPad. The Windows Phone 7 operating system will certainly feature an IE browser -- but that platform won't be available until the coming holiday season, giving iPhones and Androids some time to run away with the mobile market in the meantime.

Microsoft's online strategy has always centered on the prime positioning of that old IE browser. Would Bing have made a dent at all if it weren't the default search provider in IE browsers? I doubt it. And with even that matchless advantage apparently fading to black, month by month, Microsoft might as well give up on its online division. Heck, sell Bing and Windows Live to Yahoo! (Nasdaq: YHOO) and see whether a real web business outfit could make them work.

Can Microsoft turn this sinking ship around, perhaps with a reworked Internet Explorer 9 release? I don't think so, but feel free to set me straight in the comments below.

Fool contributor Anders Bylund owns shares in Google, but he holds no other position in any of the companies discussed here. Microsoft is a Motley Fool Inside Value recommendation. Google is a Motley Fool Rule Breakers selection. Apple is a Motley Fool Stock Advisor pick. Motley Fool Options has recommended a diagonal call position on Microsoft. Try any of our Foolish newsletters today, free for 30 days. You can check out Anders' holdings and a concise bio if you like, and The Motley Fool is investors writing for investors.