Stealing passwords from McDonald's users
This seems to be a common practice, storing UserIDs, Usernames, etc. in cookies rather than a unique SessionID that can be used to look those things up (and will expire).  I'm curious as to where people are getting the idea to build things that way.<p>Because it never would have occurred to me to do so.  Or rather, had it occurred, it would have immediately begged the question of "what happens when the user monkeys with their cookie".  Surely everybody else thinks the same way.<p>If so, how do we end up with this?  Are there really "Teach yourself in 21 Days" books that have examples with this pattern that people are following?<p>Or does everybody just assume that they're going to be Facebook with 4000 servers and no way to quickly generate or store or manage or look up those keys for millions of simultaneous users, and that it's worth the tradeoff?