While running several sites with 5 max dynamic links, I notice the same advertiser(s) appear almost every time, and sometimes in 2 or 3 of the links at the same time. I would assume these links are to sites with serious weight, but isn't this a tad lopsided?
I would assume they have more weight. The last 10 refreshes of my site showed various financial links, mortgages, credit scores, home loans...etc. I was hoping for a little more variety, but I guess those are the biggest sites. I did click one of the links last night and there were no ads on the site at all. I wonder if people are submitting links for sites that don't have any advertising.
Same here - same types of ads appear. You're correct on part 2 - "placing sites in the network that don't display ads themselves". I use sites to place ads on that already have traffic to get weight, and then place new sites that I want to appear in ads to get exposure and build backlinks to.