This new layout has been in testing since October, 2009. However, today it rolls out to most of the world. It allows users to whittle down results based on what they want to see.
Once they make a selection the left-navigation usually goes away.
We have been monitoring results for a few months when able to test while this was in Beta. However, we will continue to monitor to determine what changes this will have on CTR or other metrics. For repeated searches it seems to disappear if not selected. For example when searching for HVAC Marketing we only see it 1 our of every few searches. So, at least it knows when it isn’t wanted.
