Well, you asked two questions there. :P
To the first one, I'm not sure as I don't have a point of reference to compare against.
For the second one, I'd daresay it's possible. I think it's more about making quality hubs, which has the effect of generating traffic. More traffic equals more chances of users seeing an ad they like and clicking on it. More of your Adsense ads getting clicked on = more $$$. :)