At first I was wondering what the heck you were talking about. But I just saw this myself! There is little <> buttons on the ads now.
this is brand new feature added by google for it's publishers recently, may be to see the responce all over the world of internet users..?? or to see the actual responce with regards to revenue generation for publishers and revenue expenditure for advertisers ?? anything is possible guys ..this Google
I find them rather fun. I spent about 10 minutes scrolling through mine. I think they should add a small scabble board at the bottom of the rectangular ads as well.
The link units are really messed up now. There displaying just a search button that says "view ads" I hope they fix that soon