Matthew Bailey, SES Advisory Board & President, Site Logic Marketing
The good news is that if you follow the rules, you can pull off all sorts of site architecture pandemonium. They had a scenario where they had to simultaneously change subdomain and 301 redirect 16 million URLs and were able to pull it off successfully.
Google’s algorithm is tweaked almost daily. Once or twice a year the changes are significant and get a name, like “Panda”.
Panda was a zero-sum game. For each site that lost rank and free organic position, another site took its place. The business directory site that is a Didit subsidiary doubled in traffic, then dropped and came back. Be patient and take all also changes with a grain of salt. Changes can occur from day to day.