"Change to ads about:" New format being tested

I just saw this on one of my pages and didn't see any posts about it yet so I took a screenshot and thought I'd post it. Once I went to another page it went back to normal and I haven't seen it again yet. It's kind of like adlinks mixed with a regular block:

 

It has been posted about on a few occassions. It's been running for around a month and a half if I'm not mistaken.

 

I've seeen this new format a few days ago on one of my blogs.
I wonder if it is only working with rectangular ads.

 

This new format crops up on my site every other day. Once I reload my page it disappears. I wish Google would be consistent with this. I think visitors would click the ads if the ads were more interactive.

 

No, it shows for banner ads as well.

 

I've never see this new format on my site. maybe it is only working with rectangular ads.

 

I've seen it on all my ad formats, rectangular, square and banner. I have not seen it on the smaller rectangles (468x60 or smaller).