Sites that show up in my AdSense channel reports

When reviewing my AdSense earnings, I see the same sites more than others, which obviously are performing better than the rest. It often occurs to me that I ought to reinforce the positioning of these specific sites, by listing them in new directories I find, or getting them more reciprocal or backlinks to bolster their link strength and SERPs presence. Is it just me? Or does anyone else out there think like I do?

I agree with userpk300 ... my answer also is Google.
It's better to check it yourself also about on how you like it