unique user token

[Roger Dingledine <arma@mit.edu>]

How about using IP address as a unique user token?

Specifically: when we give the person the front page of the survey, there
is a write-in for IP address there, already filled in with the IP of
the machine that requested the page. If that IP has taken the survey
before, then it also includes a list of which user-types (home, business,
etc) have taken it. Then the person can choose a new user-type to fill in,
or change the IP if it's not appropriate for him for whatever reason, or
say that they're taking a different survey for the same user-type from the
same IP (for instance, for different people who use the same machine, or
I guess dynamically allocated dialup IPs).

(And of course, in the database itself we'd store both the IP the survey
came from and the IP that the user filled in, to help keep better track of
spoofing.)

This seems like a pretty straightforward solution. I don't want to record
the user's name or email address, because I think that's evil and easily
misinterpreted. We will have to be sure to only give a limited amount of
information based on which surveys the IP has previous filled out, so
people don't use this mechanism to figure out eg the declared income of
the user at 18.244.0.114. But I think limiting it to which user-types have
been listed so far is reasonable.

Am I crazy? Should we just stick with email address?

--Roger