This reveals two things: 1) There's not much unique about any given social site, what drives it is the users and what they post. Sure, delicious is social aro

This reveals two things: 1) There's not much unique about any given social site, what drives it is the users and what they post. Sure, delicious is social around bookmarks, reddit is social around links, pinterest is social around visual content, flickr is social around photos, so they have their niche, but the "secret" sauce is the users. 2) The layout, theme, or visual identity of a site is completely arbitrary. There's reason to make it unique as part of branding and (minor) differentiation, but they are just uniquely laid out views of the same (user generated) content. The ease at which sites can be re-skinned to look like another is the physical manifestation of the "we are the X of Y" start-up meme.