Why? If users are able to port their MySpace pages to Facebook, friends and all, then Facebook could gain further momentum in its battle for users. On the other hand, if the application gains popularity on Facebook, it could just provide more proof of MySpace's unassailable top spot among social networks.

Of course, SpaceLift is not that sophisticated. It allows anyone to pull any MySpace page into their profile, without performing any kind of check to see if they actually own that profile. And it doesn't match up MySpace friends with Facebook friends, as proponents of social-network portability, like LiveJournal founder Brad Fitzpatrick, would like to have happen. Still, SpaceLift illustrates the potential of the idea — and it points to a phenomenon that bears watching.