What is the best way to tell anonymous users apart?

Question

My company wishes to split their website so that anonymous users are given slightly different sites based on a question when they first visit.

I intend to use a cookie to store the answer to the question between sessions, but I'm wondering what the best way is to use that answer once the user is browsing the site? I intend to use page manager to handle the context but I'm still trying to determine where it should be stored:

• Cookies can be turned off by the user, or the IT department, much of our target audience have policies restricting or outright banning cookies
• Session variables seem to be the way to go, unless:
• Does the Global $user variable store different information for each anonymous visitor?

Are there downfalls in either of the latter two options? Have I missed any options?

Answer 1

Session variables seem to be the way to go

Don't forget that session variables rely on cookies

Have I missed any options?

• The traditional solution would be to use the ip address as a fallback if cookies are disabled.
• PHP does support an alternative to cookie-based sessions -- it can rewrite the URLs to include "?PHPSESSID=xyz". However, securing this can be difficult.
• Another approach would be to use html5 local storage and do all the cusomizations on the client-side. This will work in all modern browsers regardless of cookie or firewall settings.