A WebmasterWorld thread has one SEO noticing that Google is testing a new search results user interface. The new interface tends to highlight the background of a single search results, in a light blue, when a mouse moves over that result.
Supposedly, it looks a lot like the Google page previews test, but without the magnifying glass and page preview option. So I suspect it looks like this (I mocked this up off the page preview screens):
Forum discussion at WebmasterWorld.


Comments:
Reinier
10/12/2010 12:52 pm
Indeed it looks like Google is testing highlighted search results. See for instance Google UK, which currently shows highlighted search results with a non-functioning magnifying glass.
Sakis Rizos
10/12/2010 01:44 pm
Yes, that is how search results were yesterday at google.gr. Today the magnifying glass is back.
Pratheep
10/14/2010 06:53 am
Will the highlight move when you navigate using keyboard? then what happened to the blue arrow? Google is making its SERP complicated by add more elements to it. what is your opinion?
Bob
10/20/2010 08:32 pm
I saw the highlighted mouseover in the SERPS along with the non functioning magnifying glass around 9AM CST but now has disappeared.