It isn't quite a phone, but it soon will be possible to take a Skype client with you and plug it into a barenaked PC equipped with a USB port. U3, the Silicon Valley start-up launched by Palm veterans earlier this year, says it will support a portable Skype on its flash-based platform from this fall.

U3 already supports a portable email client and a bunch of encryption, caching and backup software titles. The Mozilla Foundation has pledged to make Portable Firefox and Portable Thunderbird conform to the U3 specification. Yesterday, in addition to Skype, U3 also announced support for ICQ.

It's hard to underestimate the ubiquity of the internet cafe in urban Asia, the most promising market for U3. As we've noted before, when Intel talks about 'mobility' it means lugging around several pounds of short-life hardware, cables, power supplies and dongles with you. But the most mobile technology of all is no technology at all.

Google and Yahoo! are offering old-style bureau computing to the public where the only dependency is on a browser. But given the well-publicized privacy concerns U3 may offer an attractive option.

More than two years ago we wrote about a self-funded start-up Zippy with a similar idea, which involved putting a Notes-style client on a USB stick, and charging a subscription, but the venture failed to find support. But by winning some important backing, and gathering developers behind a specification, U3 looks to have a head start.

U3 was launched at the CES show in January, is backed by two of the largest CF manufacturers San Disk and M-Systems. Its executive team includes CEO Kate Purmal, one of the first Palm employees, and Andrea Butter, the former Palm marketing chief who wrote a book about the PDA venture. ®

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