Who's reading who?

Tim Bray wonders about ways of Counting Subscribers to RSS feeds. He’s speculating about a more formal method than I’ve been looking at (seeing as, presently, my interest is purely curiousity).

In theory, IPv6 would solve some of the problems, as your IP address wouldn’t need to be NATed, and would move around with you, but that’d still make me look like two different people when I used my home computer and the one at work. The main problem I have with his suggestion of a hash of the readers email address is in explaining all that to non-techie users, as otherwise, particularly with all the spam we get these days, people will be reluctant to type their email address into something for fear of it being harvested for spam. But maybe we could use something else, like the persons name, as that’d be unique enough…