Virtual hotels

How mainstream have virtual worlds become? Somebody sent me a link to a travel blog, which normaly reports on real places, but did a post on virtual hotels. Declaring WoW dungeons as "hotel", just to get the biggest MMORPG into the series is a bit of a stretch. But the other 5 are virtual hotels all right, like Habbo Hotel or some hotels in Second Life. By reporting on virtual space in media normally reserved for real world spaces, the writer must have assumed that people are sufficiently familiar with the concept to be interested.