Hard to imagine two of the world's business leaders, one of them the world's richest man, donning sunglasses and dressing up as Morpheus and Neo to act out a spoof of The Matrix, complete with mid air leaps. That's what the Microsoft chairman, Bill Gates, did for a video he showed at the Aladdin theatre in Las Vegas on Sunday night, when giving his 20th consecutive keynote to open the Comdex computer trade show. At least it was better than the time they did a Harry Potter skit . . .

Mr Gates was a hot ticket, albeit for one night only, in a town that has warmed to Elvis, Sinatra, Liberace and currently Celine Dion. But this year, he played to a smaller audience. He filled the 7,000-seater Aladdin and there were long queues for the 1,600-seat video "overspill", but for the past few years, he has played the mighty MGM Grand Arena, which seats more than 16,000.

The move to a smaller venue reflected fears about the Comdex trade show rather than a lack of interest in Mr Gates's prognostications. Comdex used to attract well over 200,000 people to Sin City. Following three flat years in the PC market, the show organiser's brief spell in Chapter 11 bankruptcy, the effects of September 11 and the general recession, only 50,000 are expected this year.

But if the crowd had been told what Mr Gates was going to show, quite a few might have given it a miss. Sure, there were Spot (smart personal object technology) wristwatches that are updated with messages via FM radio signals, but Mr Gates unveiled that idea last year. The Tablet PC - a portable notebook PC or slate that lets users write on the screen - also appeared, but Mr Gates has featured that in his past three Comdex keynotes.

So what was new? Well, Mr Gates said Microsoft would add SmartScreen spam-blocking to all its mail software, including Hotmail. Anything that cuts down spam is good, of course, but it is not exactly a new idea.

Mr Gates also showed some server software that would help companies to install patches to block viruses. Again, that is something companies will welcome, though they would probably prefer Microsoft to ship software with fewer security holes in the first place.

And the piece de resistance was a search utility called Stuff I've Seen, which was demonstrated by one of Microsoft's senior researchers, Susan Dumais. This watches what you are doing and intelligently pops up Google-style references to other things you have seen, whether in files on your hard drive, in your email or on the web. It looked wonderful. However, if it ever appears, it will most likely be in Longhorn, the next version of Windows. That is unlikely to arrive until 2006.

Over the past few years, Mr Gates has been able to show off a stream of new products at Comdex, including four new versions of Windows (such as the Tablet PC and Media Centre editions), two new versions of Microsoft Office, clever OneNote software, the whole .Net infrastructure, and dozens of gizmos such as Windows Companions (internet appliances), Windows Automotive (for cars), wireless screens, the Xbox games console, Pocket PC handhelds, mobile phones, smart wristwatches and more.

Unfortunately, this year will probably be remembered as the year of The Matrix spoof - when the humorous aside became the main event.