I've gotten more and more submissions in the last year for pay-to-play open mikes. I'm not talking about venues where there's a cover or minimum for everyone — that's an interesting argument to have (see the many listings here where that very argument goes on), but I don't see it as particularly preying on people desperate to perform.
On the other hand: a $20 performer's entrance fee? $5 to sign up? Those need to be deleted, and new ones will not be accepted. openmikes.org exists for the benefit of the performers, first, last and always. And this crap in no way helps musicians, poets or other artists.
I'm not immediately going through all 2,000+ listings — let me know if you see one that's still here, and I'll take it down.
(Comedy open mikes are excepted from this rule, as this would otherwise eliminate a huge chunk of the listings.)