They're not the first. Hola did pretty much the same thing. If you installed the extension, you became an end node for their VPN, effectively. When they were called out on it, they added it to their TOS. I'm not sure where it went after that. Something like that, at any rate... They billed it as a P2P VPN - except they didn't even call it that until some earlier feather ruffling made them call it that. Users had no idea that it was a P2P anything at first.