Basically, it means that Google will automatically change the display URL in your ad from Subdomain.Example.com/Subdirectory to subdomain.example.com/Subdirectory.
Google automatically changes the display URLs. Many readers who commented on our original story were less than thrilled about the change. Google said testing showed improved click-through rates, but our readers were skeptical.
Let us know if this change causes either a negative or positive impact.