Okay, disclaimer at the top - there are some shows that are technically bringers but don't suffer from all the usual problems I'll go into below. The C Word in the Belly Room at The Comedy Store comes to mind as one I've heard more positive than negative about from people I respect.
Anyway, so let's start from the top - What's a Bringer Show?
Well, a bringer show is one where the comics need to bring their own audience members in order to get stage time. It's sort of like how you have to buy a drink or pay $5 to get up at most open mic's. Logistically, this is accomplished in a number of different ways - some flat out say "You are buying x number of tickets at $10 and it's your job to sell/give them to your friends," Some say "You don't go on until at least x people have shown up to support you" and some use a more subtle technique of ordering the lineup based on the size of the audience brought. (see this hilariously accurate video)
So Why are they Bad?
Well, on the surface, even the worst case of this seems like kind of a fair trade - the young comic gets stage time at something "better" than an open mic and they get to bring their own supportive audience members to enjoy. The Promoter makes some money and so does the venue - on a presumably otherwise empty room. But it's really not good for the comics - sure, you get stage time and out of the open mic ghetto. But now you're in the Bringer ghetto. I can't tell you how many stupid Facebook invites I get from the same people doing a bunch of bringer shows every week. You know what? I never get invites from those people to actual shows.
The other thing is, there are a BILLION small rooms in this town where you can get stage time for free if that's what you want. Sure, you might be shouting over the music downstairs at Red Rock or have to get in your car and drive to the Valley or the burbs, but there's your stage time. And that's where you're going to meet the people who are a little (or sometimes a lot) ahead of you who will want to help you book other gigs because they admire your work ethic, they think you're funny, or they just like you because you let them bum a cigarette.
So, I'm not just writing this to bitch about shows that are run a certain way that I happen not to be a fan of. I actually want to tell all you comics out there Stop Doing Shitty Bringer Shows! It's the only way the practice will come to a stop. Every respectable venue in town has some kind of bringer show in one of the rooms on some night - and why not? It helps float the other nights when even great talent doesn't sell enough tickets. And the promoters sure aren't going to stop. Most of them are comics who need to support themselves and would rather it be comedy-related than "Would you like the Grande or the Venti" related. I honestly can't blame either for seizing on the opportunity.
So the only person in the system with any motivation to stop is the comic in the show. So Stop. Bring the economy of comedy back into the free market and don't subject your friends to a bunch of other horrendous acts.
Second disclaimer - Who the fuck am I to be judging you and your goals and your road to success? The comments are open if you want to excoriate me for saying this because you think I'm being unfair or naive. This is just what I've seen in a very short time by watching and listening to people I really admire.
Third disclaimer - You could accuse me of having sour grapes here. I actually don't have 2 friends who are not comics in this city. Well, actually I do, but I like those 6 people too much to ask them to come to a bringer show.