There's also another pretty nice feature in WoW which was also present in lesser significance on battle.net: The /who command.
It's a lot more powerful in WoW mostly because there are more variables for each player on the game compared to the games played on battle.net
You can include level, part of name, class, race and location. For instance, if you were looking for a Warlock in Tanaris to summon you to Gadgetzan, you could do the following:
/who Warlock Tanaris
If you're racist and want only a Gnome Warlock:
/who Gnome Warlock Tanaris
If you met someone a few days ago and want to talk to them, but have since forgotten their name, you can use a level range. If you knew your friend was level 34 druid a few days ago, chances are they're levels 34-40.
/who 34-40 Druid
There's also some weird formatting you can do that is ultimately useless. I'd guess it exists to provide some clairty to anyone else you show the command.
/who c-"<CHARACTER NAME>" l-"<LOCATION>" r-"<RACE>"
I'm pretty sure there are some more letters you can preappend values with, but I haven't cared enough to check into it.
The scripting interface for WoW is also pretty powerful.
This WoWWiki page provides the best reference for it that I've ever come accross.
WoWWiki is just about the best reference (for general knowledge.
Thottbot and
Allakhazam are better for more item specific inqueries) for WoW in general you'll ever find. It has information on all the zones, characters, lore, instances, etc.
