Gates in 2002. (Microsoft photo)

Give Bill Gates and Microsoft credit for seeing the potential of Tablet PCs long ago. Microsoft launched its inaugural Windows XP Tablet PC Edition back in 2002. But despite the Microsoft chairman's interest in the technology, the Redmond company was never able to expand the tablet computing beyond "niche" markets, in the words of Ray Ozzie, Gates' successor as chief software architect.

Now comes Apple, which is widely reported to be working on a tablet device of its own. After watching Microsoft struggle with this market for years, it would be interesting to see Steve Jobs & Co. give it a try.

For starters, Apple would be approaching tablet computing from a very different perspective. Whereas Microsoft started with vertical industry segments, such as health-care workers, Apple's existing business puts it in a position to start with the consumer market. Whereas Microsoft and its hardware partners marketed Tablet PCs as new types of portable computers, Apple can market its tablet as essentially a larger version of the iPod touch, with an existing base of applications.

Whereas Microsoft had to convince people to adapt to pen-based computing, Apple has already gained widespread acceptance for a touch-screen interface, thanks to the iPod touch and iPhone.

Lots of questions surround the possible Apple tablet device, price being primary among them. But with the Mac maker's move into tablet computing now a widespread assumption, it will be interesting to see how -- or whether -- Microsoft reacts.

Following Ozzie's comments about Tablet PCs last year, Windows chief Steven Sinofsky reiterated the company's belief in tablet computing, particularly given the touch features in the upcoming Windows 7 operating system. A while back we heard rumblings that Microsoft Xbox and Zune guru J Allard was working on some sort of Tablet PC revival. But we haven't heard anything since.

Could Microsoft end up playing catch-up in a market it tried to lead?