Why isn't there a Yelp for apartment buildings?

Don't you wish you could know what it's like to live in a certain apartment or building before you rent it?  One way is to talk to current tenants - but most of the time the current tenant isn't going to be truthful to you.  Especially if he/she is wanting to break their lease early and that's why they are showing you the place!  Don't believe those stories about moving across the country - most likely they are trying to escape a bad apt situation!

At least that's what I was doing!

I hear so many people who say "I wish I had known the apt would be so hot in the summer before I rented it."  Or "I wish I had known the super would be useless before I rented it."  Or "I wish I had known the landlord is a drug lord before I rented it.  Or "I wish I had known the hot water never works before I rented it."

Why isn't there a community site like Yelp where users can comment and rate their former apartments?  Wouldn't that be useful in NY?  Or would that be so discouraging to people that no one would ever move here again??