What I'm thinking is a service that uses Glacier to store my photo library and some type of front end service (like dropbox) that keeps a low res version of that photo along with some meta data about it.
My reasoning for this is that we all build up pretty significant photo libraries (mines already over 60GB) and I'm always trying to make sure I have them backed up. I currently use a paid plan at Dropbox so I can put them all up there but it's kind of a waste since I hardly ever pull many of them down again. Every once in awhile I browse through them looking for certain pictures that I might need to get a copy of (which is why I'd need the low res copies easy to access/browse) and then be able to choose which ones to pull down from glacier. The other good thing about a service like that is the need is not typically immediate.
Maybe I'll look into building this since it's something I'd love to have for myself!