My rent is $1050 / month, I live with two friends. Adsense pays me per click, but when I charge advertisers, I charge them CPM.
August - 150k uniques
Sept. - 100k uniques
Nov. - 140k uniques
organic = ~20%
referral = ~30%
direct = ~50%
I don't get direct advertisers often, but when I do, I charge them anywhere from $2 - $5 CPM (obviously it depends on the company)
Edit: I forgot to mention, the AMA title was "I run ThatHigh and it pays my rent in SF" so I guess it's safe to say that he makes at least $1050/mo from the site.
From my experience, 500,000 pageviews a month will turn a decent profit. Absolute minimum seems to be 100,000 a month, which is extremely easy to obtain these days.
I consider 100,000 pageviews a month easy because I can achieve that number organically (without paying for traffic) within a few months.
My niche is probably a bit easier than some others, though.
I also consider it easy in comparison to the fact that it took me 2 1/2 years to get to 600,000 a month when I first started. I could probably do 600,000 organically in half the time now.
If you are just throwing up a generic banner ad network, it's probably close to $.10-.25 CPM. Then multiply by how many ad units displayed per page (networks usually don't allow any more than 2-3).
So: 100,000 * .00025 = $25; x3 = $75
Very rough estimates. With a site with such a particular niche, he can probably get a higher CPM. I also count 7 ads on the home page.
Well, it's public how numbers vary so much. Mine's a niche music site so I don't think I should expect much more than what it's doing right now. I could easily improve the banners placement though, I just think it isn't worth it.
ps: I guess quite a few of us have such "Oh that would be a fun site" ideas... I just don't know what traffic will make it worth the effort.