It runs a Linux distro from Wind River on an embedded low-power architecture (processor not specified), which means instant on/off and a set of built-in applications that run in full-screen mode - so it's more like a Palm PDA or a Pocket PC than a full-blown laptop - but it's open enough that Palm is encouraging third-party developers to build applications for it. At LinuxWorld yesterday Palm announced that one of those apps will be a version of LogMeIn's remote-access software.
Palm has worked hard to make the Foleo sound like an accessory for its Treo smartphones (see early reports like the one from PC Magazine, for example), which is one reason for the ridicule it got - who needs an accessory that's several times bigger than the device it supports.
But I think that's just marketing spin. Maybe Palm actually believes it, maybe the company itself doesn't understand the product. For me, it's the WiFi ithat makes this device something to take seriously. It will function as a stand-alone ultra-mobile PC-like device, and at a $500 price point it's half the price of anything similar out there.
The only thing that bothers me is the suspicion that at 2.4 pounds it's too big - I keep hearing that by next year we'll be seeing 1.5-pound UMPCs. (The counter to that may be the Foleo's ISO-standard 18mm pitch keyboard - I haven't seen anything smaller that's seriously intended for touch-typists.) We're going to see a lot of very small devices in coming months as Microsoft's Origami platform sorts itself out, and the worst thing that could happen to the Foleo is that it would turn out to be a transition device - too advanced to get much traction at the early phases of the market, and too retro to cash in when buyers finally figure out what they want.