On closer look, the links go to googlesyndication. Upon looking at the HTML code, they are indeed Adsense ad units.
Anyone seen this format style before?
On a similar note, many people are discovering other new test format.
- Jensense reported New AdSense “Vertical Images” within ad units
- Problogger reported a year ago of a test Fully Customizable Ads Blocks. Have not seen those around yet.
- Another format is the “Change to ads about” format where you can change the ads shown. I had seen this on some of my sites and didn’t realise it!
Update: It seems like this was an old format that had appeared before.