Reading the API docs, it seems that every user needs their own URI to be uniquely identified. I wonder how this will work with the average user, just IP address? What about users with shared internet?
You're correct-- we anticipate users either registering their own domains (i.e. http://danielsiders.com) or using a hosted service that provides subdomains (http://danielsiders.tent.io). If you're hosting at home (dream solution here is plug computers), then dynamic DNS pointing to your home IP/computer.
This was the mistake Open ID made, which they later realised complicated things way too much for the average user. Regular users want to identify as an email address, not a URI.