Microsoft's next-generation OS, Windows Vista, continues to be horribly late, but that hasn't stopped the current version, Windows XP, from dominating the OS market. Web analytics company OneStat.com says that XP is responsible for almost 87 percent of all Web usage, while all Windows versions combined account for 97 percent of Web usage.

"Microsoft's Windows dominates the operating system market with a global usage share of 96.97 percent," OneStat.com reports. "The leading operating system on the Web is Microsoft's Windows XP with a global usage share of 86.80 percent. Microsoft's Windows 2000 has a global usage share of 6.09 percent and is the second most popular OS on the Web."

You read that right. Windows 2000 is the second most often used OS on the Web, with almost three times the usage share of all Macintosh versions combined. During an event keynote last week, Apple CEO Steve Jobs was quick to point out that Mac OS X was "gaining market share," but Apple has made only concrete gains in very specific markets, such as "retail sales of notebook computers in the US." In reality, Mac OS X usage is still below 2.5 percent worldwide. Even the 8-year-old Windows 98, with 2.68 percent of the market, accounts for more users than OS X does.

Many had expected Apple's recent successes with the dominant iPod MP3 player and the move to Macs that use Intel chips to increase the company's share of the OS market. That hasn't happened yet, although it still could: With Vista not scheduled for general availability until early 2007, Apple has an opening during which it can sell Mac OS X systems to Windows converts while pushing its next-generation OS, code-named Leopard.

According to OneStat.com, the following are the most frequently used OSs on the Web in the world:

1. Windows XP - 86.80 percent
2. Windows 2000 - 6.09 percent
3. Windows 98 - 2.68 percent
4. Macintosh/ Macintosh Power PC - 2.47 percent
5. Windows Me - 1.09 percent
6. Linux - 0.36 percent
7. Windows NT - 0.24 percent