Location-based building chat application

Apartment buildings are a whole community of people who normally don't meet or see each other on a day-to-day basis. I think the is a market need for people in apartment buildings to have a chat application.

Problems to be solved:

• When a neighbor is playing music too loud, how do I contact them and let them know? I could go up to the door and knock, but depending on what city/area you live in, that can have very mixed results.

• When I am giving away free stuff that I don't want anymore (like a coffee table for example) how can I get the word out? The next best option is knocking on everyone's door, or you put it next to the garbage which has a stigma.

• If I'm looking for new people to hang out at a local pub with, how do I get the word out?

I think there are a lot of benefits from a user perspective to being able to access this network of people.

The only issue is, I think making money would have to be charged to the landlord, which is a hard sell. I think you could do the advertising thing no problem, but the scale to make that work is unachievable for most apps.

One thing that could work is having public messages free, but sending private messages can cost money. Like a one-time fee of 10 bucks to buy the app. Responding is free, but sending the initial message is a premium feature.