It was only for those who wish hotlinking, and a fast service, that also officially supports cross-platform software. But yet another alternative for cloud storage is Live Mesh, which have 5 GB like OpenDrive, but shamely requires an invitation to be used and doesn't have hotlinking either.
You can expand your Drop box space by sending an invitation link as I did. You get 250 MB extra space for each invitation. So you can actually get up to 5 GB space, as long as you send enough invitations. :)
But GmailFS gives you the possibility to use Gmail as an virtual file system with files and folders. Gmail offers about 7.5 GB space. But of course, these are nasty hacks, and should be avoided.