In response to your questions:
1) Town rings are an old tradition in which above every town there would be floating rings so newbies know its a township. You can ignore this now though, they are no longer in the game.
2) Mob spawner grinding is killing mobs that spawn off a spawner to earn xp. This is now illegal and you will be banned for doing it. (Unless it is a 'safe to use' designated mob spawn (located in spawn) )
3) The term blinking comes from the Wizard skill Blink. Blink allows your to teleport a certain distance to where your mouse is pointing!
4) Block jumping is a form of exploiting where you use region lag to jump up to/out of areas you wouldn't normally be able to get to. Eg. Someone might 'block jump' out of a deep hole.
5) Joining a town is not mandatory but instead is highly recommended!
Welcome to Herocraft
Check your PMs
@
Shdggsdv