This particular test by Yahoo with their search result ads is definitely a blast from the past.  They are testing search ads with a pale blue background.

Those who have been around the industry for a while will remember when colored backgrounds – first blue then yellow, along with some random test colors along the way – were always displayed behind ads in the search results, as a way to separate them from the organic un-paid search results.

It would seem Yahoo is going old school with these search result tests I spotted.

They are testing it out on Yahoo Canada, so you may be able to replicate it here.  I tried a few other country versions of Yahoo, and none of them were displaying the blue background on the search results.

It is definitely fascinating that Yahoo is testing something that the search engines abandoned several years ago, and on an international version of Yahoo.