NB: You're probably better off using put.io adder by @nicoSWD.
I like put.io's service, but I hate copy-pasting magnet urls to and from Safari. So I made this little app, that handles magnet:-urls and sends them to your Put.io-account.
Well, this is as crazy as it gets:
Here's a pre-built version that should work: Putter.app.
It should probably also handle .torrent-files?
Do what you like.