Paradigm-seting open-tagging system for organizing and sharing photos. Though it does not bear directly on the Transliteracies problem of online reading, Flickr is relevant because it helped establish the model for open, shareable metadata—that is, for allowing users to annotate online resources in common:

“Part of the solution is to make the process of organizing photos collaborative. In Flickr, you can give your friends, family, and other contacts permission to organize your photos – not just to add comments, but also notes and tags. People like to ooh and ahh, laugh and cry, make wisecracks when sharing photos. Why not give them the ability to do this when they look at them over the internet? And as all this info accretes around the photos as metadata, you can find them so much easier later on, since all this info is also searchable.” (from About Flickr on Flickr site)

Starter Links: Flickr home page