g1smd - 11:19 am on Nov 17, 2012 (gmt 0)

A site previously with 80 000 duplicate content URLs now redirects and canonicalises those to 1500 product pages in a completely new URL format. There was a dip for a few weeks but several months later traffic is higher than it ever was. There was a long period where old URLs were still listed in the index, but some of those still brought traffic.