True Sharing vs Fake Sharing

Lawrence Lessig on a key difference between YouTube and Flickr:

So there’s an important distinction developing among “user generated contentâ€? sites — the distinction between sites that permit “true sharingâ€? and those that permit only what I’ll call “fake sharing.â€? A “true sharingâ€? site doesn’t try to exercise ultimate control over the content it serves. It permits, in other words, content to move as users choose. A “fake sharingâ€? site, by contrast, gives you tools to make seem as if there’s sharing, but in fact, all the tools drive traffic and control back to a single site.