My first post on this forum in forever and it's on *this* topic. (freaking bot using @everyone).
Anyways, I don't mind @here since it only notifies you when you are logged in/have the program running. It's useful when you're trying to get people on a small server to play video games or what have you.
@everyone has two uses:
1) Annoy everyone everywhere
2) Notify people of important stuff (server announcements, Strat-op fleets for EVE, etc.)