AH: hero-side auction house. Wentworth's ($ icon on your map)
AT / Archetype: in a broad sense, this would be your 'character class'.
Blue / Blue-side: Refers to Heroes.
BM: villain-side black market. villain version of auction house.
DO: dual origin enhancement
Exemp / Exemplar: artificially lower your level to that of a lower level character.
INF: influence (hero), infamy (villain) - COH's "money"
IO: invention origin enhancement
LK / Lackey: artificially raise your level to one level less than that of a higher level character.
Mal / Malefactor: artificially lower your level to that of a lower level character.
Red / Red-side: Refers to Villains.
SO: single origin enhancement
SK / sidekick: artificially raise your level to one level less than that of a higher level character.
TO: training origin enhancement
What makes City of Heroes different than the other MMOs I've played? What are these differences, and how do they affect me?
--There is no grind-treadmill at the "end game" where you go thru a dungeon 50+ times so everyone can get that dungeon's armors, only to rinse and repeat for the next dozen+ dungeons. There is, however, lots of "end game" content.
So, if you're looking for a game that will force you to team with 10-30 other people in order to grind the exact same instance dungeon 50+ times in order to get that next tier of gear; and then repeat that times another dozen+ dungeons -- this isn't the game for you.
--All content is playable / replayable no matter your level. This means you will obtain loot no matter your level or the content's level. This is thru the in-game mechanics of lackey/sidekick, malefactor/examplar and Ouroboros.
--The versatility available to you in all the ATs, means that you never have to search for that perfect team to do any missions. There is no holy trinity of tank/dps/heal in this game. Honestly, the power of team buffs combined with enemy debuffs, precludes the need for a "healer" at all, assuming even semi-intelligent game play.
--Heals, for a team that plays intelligently, are easily the weakest powers in the game, especially compared to holds, confuses, debuffs, buffs, etc.
--Super/Villain groups are able to build bases which allow you to teleport to all of the zones, store inspirations/enhancements/salvage, have places for group relaxation and even your own quarters.
Good to know information available to you before ever signing into the game:
--the official COH forums: http://boards.cityofheroes.com/ubbthreads.php There is a wealth of information available to you on everything in this game, especially tips/tricks for the various ATs.
--Vidiotmaps.com << get an ingame map overlay from here. This will show you the level of the mobs in any zone you're at currently, plus location of various badges, giant monsters, and other points of interest.
--download mid's hero planner, or use suckerpunch's online version ... they're found @ http://www.cohplanner.com/
For a lot of this series, I'm going on the assumption that you've done a little more than install the game software on your hard-drive. I'm going on the assumption that you'll have gone to the above sights and done a little reading and have at least familiarized yourself with badges and how to read your map.
I may also be returning to this post (and others) in order to expound upon information presented, correct erroneous information, etc.