Also people will assume you're a jerk, if you're in a guild full of jerks.

Odd thing, as a mostly solo player, who does not hang out on realm forums, I have no clue what any guild's/player's reputation is. It doesn't really show in game. (this is probably the reason I have no idea about finding a guild to apply to)

May be one of the reasons that add to the anonymity people feel in WOW. If you are only interacting with the guildies, that is your world. So, if you don't have the inclination to act reasonably on your own, there is no check on your behavior. Your guild is the only place where you may ever be called out on this. If they don't do it, you never get any feedback that, no, it's you who are the problem not the world, and you are likely to continue being an asshat.

I believe that the way people act in the game world is really how they are in real life their just in the closet about it. A D-Bag in this fake world will be a D-bag in the real world.

@Toothy

While I may not be a solo player like you, I too avoid the realm forums, but I don't agree that player/guild reputation is not apparent in the game. If you spend any time in the Trade, General, Guild, or Local channels, you will often find out quite a bit about people on the realm.

For instance, there is one player on my server, who constantly trolls trade chat, and as a result, has been banned from many PuGs that get going, and has been booted from multiple guilds, even though from my experience, he is a rather skilled player.

Likewise, there is a very large guild on my server that has gotten a bad reputation for having ninja looters in the guild, even though any time the GM finds out about a ninja looter, they get a quick /gkick, as he doesn't tolerate that. The guild itself has some very good players, and nice people all around, but because of a string of bad apples, they have gotten a bad name.

Saying that reputation doesn't show unless you are in a guild/on the forums seems a bit like having blinders on to what is going on in the game.