I respectfully suggest that if you want developers to use the Sync API to reinvent "the internet" in a fully P2P way, they will only do so if you let them - which means no central control mechanisms such as API keys. I suspect that the very last thing you would want is legal responsibility for how the API is used, which you would probably have if you were able to shut down "reported as infringing" clients via their API keys. Imagine for a minute that you could be held responsible for each Bittorrent client in use. You would be forced to accept and process take-down notices for each reported abuse, the RIAA would have (had) some fun, the Bittorrent protocol would not be used by anyone anymore today (or rather, nobody would use your client), and the MLDHT would not have the strength needed to reinvent the p2p internet on top of it. In a nutshell: if you go truly P2P by fully relinquishing any technical means of asserting central control, I strongly believe that you could end up as the underlying plumbing for a lot of exciting stuff. But if you artificially recentralize your (by its nature) true p2p plumbing via api keys... nope, then there will be something else used instead (see redecentralize.org) (possibly/probably using the bittorrent protocol and the MLDHT, at least to bootstrap, and who knows, maybe a reverse-engineered BT Sync protocol... but surely not your centralized client). So... there is so much exciting potential here, please let us use it to its full delightful extent! And thank you for providing it.
