Ok, I think the concept is interesting, the site is nice, and this could be popular in a down economy. However, here are my two concerns:

a) Selling space in your house by the night this way most likely violates one or more state/local laws. First, you're probably not operating with a business license.

Second, most cities have specific "bed taxes" (often 10% or more) for hotels. This is a significant source of revenue for touristy cities. Some cities also have specific laws about vacation rental properties (some actually don't allow rentals for less than 30 days)–even though I doubt these arrangements would qualify as a vaca rental.

b) I'm no lawyer, but once you let someone pay you to stay at your house, it seems like you put yourself at a greater risk should someone get hurt or sick at your place. The last thing I want is some dude to pay me $50 to spend the night and then slip and fall in my shower ...

I think couch surfing gets around this by acting more like a personals/ride-share/craigslist site that connects people. I'm not saying ABB will get in trouble–just that it may not catch on as quick.

I'd rather pay $20 more and avoid the awkwardness of sleeping in some guys living room.

They don't seem particularly cheap either. Most hostels are much below the prices listed.

I use couchsurfing, which is free, and whose goal is to meet other travellers, not to get a "cheap" stay.

Depends on whether there are cheap hotels in the part of the city you want to stay in.

Haha but some places the difference can be $100-$200.

I don't know man, it would still be something I would try as hard as possible to avoid. After my last big 6 month trip, I'm sick and tired of staying hostels. The last month of the trip, I stayed in hotels only. Being able to scratch your balls in private is worth quite a lot of money, in my opinion!

What is this different from http://www.couchsurfing.com/ ? Less people? Better layout? You even have to pay?

You're thinking like a guest, not like someone listing a room. It's pretty obvious how it's different in that case.

It sort of reminds me of the difference between Greyhound and Bolt Bus/Megabus

I have to ask, what is the difference?

I think the barrier to entry (money, online access, etc) helps clear out the trouble makers. Sort of like making users register in order to comment.

Bolt Bus can only (for the most part) be booked online and has free wifi. It also uses variable pricing based on demand (initial tickets usually are priced at $5 or less). Greyhound sort of does this, but it doesn't change as much. Consequently, Bolt Bus attracts professionals, college kids and much more uh...civilized...client base than Greyhound. At least that's been my experience and my friends' experience as a frequent user of both.

this is a business. couchsurfing is the open source equivalent :)