Dell has filed a cancellation request with the USPTO for Psion's trademark on the word "netbook," which, as Dell asserts, has become a generic term for small, crappy-but-cheap computers that everybody wants for some reason. Psion did actually use to make something called The Netbook, but it's really old and they haven't sold it for a long time.
As Rob points out, Dell's been very careful not to use the term so far—so has Sony, though it's more of a marketing thing for the Vaio P—but obviously they've got their eye on it. Given who's fighting who, I'd squeeze the word tight, since they aren't going to own it for a whole lot longer. [USPTO via BBG]