My forum is a low niche. - www.teenhut.net But I am happy with what I am getting, I think only more traffic should improve it. And why I am happy is adsense isnt only revenue, banner ads and text link ads all together makes me happy
It is very much possible to rack 1$ from each of the 100 websites. You must, however, take time and SEO each and everyone of these websites to get more overall traffic. 5k is nice, but not enough for all 100 websites.