Trustsurance: There are a ton of websites starting up now that do useful things with my personal data (calendars, todo lists, links, whatever). I wouldn't call them web applications; they're too lightweight for that. They're utils. If we were on Amigas, they'd be distributed on Fred Fish disks, that kind of thing.
Only... if I have a utility on my computer and the developer disappears, I'm fine, but if the developer of one of these websites goes, I'm screwed. I know they don't mean to disappear, but if they don't get enough users then they won't get acquired and they won't be able to stick around. And after the first site vanishes, no users will sign up to the others either, so nobody gets acquired. What these sites need is a guaranteed "your data's safe" clause.
Business concept: User data insurance. This insurance company offers its services to all independent Web 2.0 outfits. The outfit pays $$ for insurance. In return they can guarantee their users that, should they go under, the insurance company will host the user data for 1 year in a downloadable format, plus a minimal read-only browsing tool. The website can put a little badge and reassuring message on its front page. In the spirit of neologism and the times, I call this Trustsurance 2.0.