I wonder how much junk like this gets through Adsense. I would have thought Google keeps the ads on their network under tight control. But I see tons of reques

I wonder how much junk like this gets through Adsense. I would have thought Google keeps the ads on their network under tight control. But I see tons of requests to other domains even on pages with just one Adsense ad and no other external content. Example: googlesyndication.com google.com voicefive.com gwallet.com doubleclick.net doubleverify.com mediaplex.com scorecardresearch.com t4ft.de r1-cdn.net afy11.net dotomi.com All contacted multiple times on a single pageview with a single adsense ad and no other external content. What is all that?