How much could an article site make on adsense?

[crick]

I bet they make lots because they are ranked about 600 on Alexa. Great thing (for them) is they are making it on the back of other people's articles.

[Heartlander]

Sure they are making money on others.
The magic is that it is "user-content-driven".
A lesson to be learned here.

Nothing unethical about any of it, IMHO.
The fact remains that by submitting articles, other article submission services pick them up as well, and the author gets his/her link noticed in a big way, oftentimes earning them money in return via their own site monetization.

There are thousands of articles out there on just this topic alone ; )