Of our predictions about Macworld this year, the subnotebook likely topped the list for most mentioned, and though the name MacBook Air sounded strange to me when I first heard it (come to think of it, it still sounds weird, unless this is actually a product made out of hardened atmosphere), it looks like the evidence is mounting. Over the weekend, the name appeared in an Adium X usage log, and now we've got news that search engine ads and domain name lookups all point to Apple as the owner of macbookair.com (even if the site itself doesn't).
So is this the name of Apple's new subnotebook? Of course, we won't know for sure until Steve says it on stage, but while it's not, on the surface, Apple's best naming choice, it could work, in an "Airport" and "Air Tunes" kind of way. It could be worse-- the thing could be called the MacPod. Or the PodBook. Or the PodMac. Or the Lisa.
Update: macbookair.com isn't owned by Apple, but by some merry prankster. Let the speculation continue!