pretty sure he makes money when folks pay him to have the site cache the pages you bookmark in case they go away. Also allows you to search the content of the bookmarked pages, not just the stuff you typed in when bookmarking it.

I don't check how quickly the cached copies are created after bookmarking. All i knows is that they're there when the site has disappeared. He's got about 7.8GB of stuff stored for me and i've been happy with the service.

They charge for the service, although IIRC they do have a free version with limits on number of bookmarks.