in reply to 2000 cURL Request
Ideally, the way you should do this is start a relationship with the web site's API, which, when asked nicely, would tell you when a particular user was most recently changed (assuming you're looking for updates to that user).
Once you had that information, you'd be able to get details on just the users that were changed, saving you and the web server lots of wasted cycles.
Alex / talexb / Toronto
"Groklaw is the open-source mentality applied to legal research" ~ Linus Torvalds