Ladies and gentlemen who run dungeons in 2011, if I could offer you only one tip for the successful instances, crowd control would be it. The healing and tanking benefits of crowd control have been proven by thousands of PUGs and guild groups, while the rest of the internet's sea of elite advice is the theoretical ravings of armchair quarterbacks. They will dispense that advice daily. Some is true, some is probable, but not all of it is absolute. But trust me on the crowd control. There is very little you can do to improve your dungeon experience than execute crowd control and not stand in fire. Today, we will focus on crowd control.
In the days of yore, crowd control mostly meant Sap and sheep (which is to say, Polymorph). But as content patches and expansions grew over the years, the concept of crowd control has grown as well. Now, you have slows, snares, traps, debuffs, fears, and every combination you can imagine. Every class has some form of crowd control.
Essentially, the job of crowd control is to slow down or keep a mob from doing the damage it wishes to your group.