Yes, that is a good point Neil.

That said, I'm a member of various websites that require sign-in, and I can access them on my mac at home, or on my mobile phone PDA. I don't store cookies on the phone so I have to log in every time I want to post or buy something, which can be a fiddle, but it's not really a problem. It's not two identities, just two doors into one identity.

Or people can read at work, then save up their contributions until they get home.