Anchr

This is rather just a free webservice than an actual startup, but you might still like it or find it useful.
Anchr provides you with kind of a toolbox for tiny tasks on the internet. Currently you can upload and share pictures, shorten links for easier sharing and create link collections, which are like a bookmark list that is accessible from everywhere. Awesome features like a message board, a notes book, a poll service and many more are about to come.