flickr. I was inspired to create a group called "Spolia," which does just what it says on the tin. Thus far it's mostly my own photos from Central and South Italy, but I'd welcome contributions from far and wide.
Spoliation is much easier these days. Texts, images and other such fragments can be embedded in new creations with a few clicks of the mouse; you don't even have to wait for the original to crumble into pieces.