Certainly. Thousands of sites earn more than $1000 a month. But the site owners don't hang around this forum bragging about their earnings and listening to people complaining about making $1 a day. It's easy to get the misconception from this forum that nobody makes more than a few dollars a day and that it is not even possible.
No, Shoemoney makes 130k per MONTH, or at least during that one month in 2005. I don't know who Markus is though, is that the guy from plenty of fish?
Got my first 1000 in mid 2007. You can earn that too. Content X SEO X Keyword Research X Ad Placement = $$$
You can make good money from Adsense. But affiliate marketing is where the big money is. Most people don't do it because they are too lazy though.
It's possible for anyone to get around that number but takes a lot of work and perhaps few year's if you don't get lazy like i am. I'm happy to pay for my hosting bill with Adsense. Other folks make mortage payments with adsense check's. lol
There is no limit to adsense earning. You can earn millions of dollars provided you have a good website with a lot of traffic