Judging from the spectacle here at the Jacob K Javits Centre, last week's PC Expo might as well have been called PDA Expo. The buzz from the major handheld vendors, Palm, Handspring and Sony was deafening. Everywhere I went on the show floor, people were either hawking, gawking or using handheld computers; you couldn't miss them. Wide-ranging trade shows like PC Expo serve as a good barometer of the industry and its direction. By that metric, it looks like we'll be ditching our desktop PCs and laptops in favor of wireless handheld computers and by this time next year there won't be a need for any other type of computer. Major portable announcements at PC Expo included a coming-out party for the Sony Palm OS-based handheld computer, an expandable platform for future Palm-branded handhelds (called SD), and even more cool Springboard expansion modules for the Handspring Visor. The biggest buzz of the three announcements surrounds the much-anticipated and as-yet-unnamed Sony handheld. The device, which is only being shown "under glass", is only a prototype, and it looked it. Although Sony has the potential to make a really killer PDA, the product is still more vapour than substance. The Sony Vaio Penner (my name for the PDA) is oozing with potential with its cool industrial design, jog dial and Memory Stick expansion slot. Meanwhile, Secure Digital (SD) promises to extend the scope of future Palm handhelds. However, both products bring to light some serious compatibility problems brewing in the handheld space. The Sony and Palm announcements mean that there are now four incompatible standards for handheld computer expansion: Handspring uses the Springboard, the TRGPro uses Compact Flash, Palm uses Secure Digital, and Sony uses memory stick. As a consumer, this welter of technologies means you won't have an easy way remove an expansion device from your handheld and pop it into a colleague's -- unless of course, your associate is using the same brand. While it's true that you can always beam a file among any of the four devices, that workaround can become cumbersome when it comes to sending anything larger than a few kilobytes. Furthermore, you definitely can't beam your hardware MP3, GPS or cell-phone module to another device. If handheld systems all used one expansion standard, you would be able to share peripherals among devices; that would in turn inspire developers to create more modules because of the larger installed based of potential customers. Imagine for a minute that your Palm, Handspring Sony or even your Windows CE/Pocket PC portable computer had a slot -- along the lines of the venerable PC Card technology -- that could accommodate CF, SM, SD or Memory Stick cards. You could install a universal adapter of this sort could in your device, your colleague's PDA and even your laptop. Lacking a solution of this sort, consumers are left holding the bag when it comes time to purchase a handheld computer. The expansion format that is best for you will depend on what other peripherals and devices you own or are thinking of buying and what devices your co-workers, friends and family are using. Sowing confusion among potential customers is a bad thing: Just consider the thicket of incompatible mobile-phone standards in the United States -- CDMA, TDMA and GSM1900 -- which have stunted digital cellular growth compared with countries such as Finland, Sweden and Japan. PDA makers are cultivating similar barriers to entry; hopefully, their development efforts won't choke off the vitality of a market that seems poised to reach new heights. Jason D O'Grady is editor in chief of Go2Mac.com and PalmLounge.com. What do you think? Tell the Mailroom. And read what others have said.