news:eW**************@TK2MSFTNGP02.phx.gbl...
You're right: he can move to another computer,Or simply delete the cookie...
but it's better than nothing.Not really...
This sort of thing is almost impossible to implement to the extent that it's
hardly worth the bother of trying...
The best solution would something along the lines suggested by Jon. Also, if
you're really worried about people doing the survey more than once, you'll
need to email the login credentials to them and, obviously, disallow free
email addresses from providers such as HotMail, Yahoo, GoogleMail etc...
People usually think twice about having to sign up for a tarriffed email
address *just* to complete a survey more than once...
--
Mark Rae
ASP.NET MVP
http://www.markrae.net