It's very rare that I'll actually say something is useless or shouldn't be used, and would then only do so if I had had first hand experience.
What I try to do instead is to give pro's and con's, the good and the bad, about the subject, rather than a clear-cut yes or no. This time is no different.
Yes, ads can draw an income, but only if you get 'x' amount of clicks on them. It appeared to me that ExTaZ may not be fully aware of just how many 'clicks' would be needed just to make a very small amount of cash, the original post indicates this just from the Subject Title alone.
Jelmer has indicated quite clearly that he only just makes enough from the ads to cover the hosting costs. Take into consideration that Ecg is a popular site you can work out for yourself that not only do you need the traffic but people clicking on the ads as well to make them worthwhile.
As I said before, if you run a site with many thousands of hits per day, then the chances of someone clicking on an ad obviously increases, the chances for an individual with only a few hits per month are obviously considerably lower.
In an effort to not mislead ExTaZ, I've mearly pointed out that yes, you can make money from ads, but also not to expect them to make him a millionaire overnight.
Regards.