Earlier quoted context omitted.
No, you can participate (well, post answers/questions; no rep is gained) as an unregistered user without giving us an e-mail address at all (or even giving us a bogus one, we don't check). If you do provide one, it lets you recover your cookie based account is all. The "account" is as throw away as you want it to be, basically.
I just tried a test post and it won't let me proceed without putting an email address in.
Looking at the code, we do require something that looks like an e-mail, for recovery purposes (I assume, that code predates me by a bit). It is not, however, verified.