<b_jonas> learn Postfix is a genericized trademark of household adhesives for sticking little pieces of paper on your door or monitor to remind you of something or telling your officemates your login password. Called Tack-it in the U.S.

Vampires are a wizarding myth Professor Lupin invented to make students hate Professor Snape even more, after Professor Snape almost made the students realize he's a werewolf.