Summary
HTML optimization of two similar sites has led to a total loss of pagerank (certain links fell from page 1 to 100). No URLs were changed, neither was the visible content. Why are we punished for cleaning the code?
Explanation
I am the webmaster of a non-profit organization that donates grants to colorectal cancer research projects and funds various colorectal cancer information campaigns.
We have three domains:
www.fundacioolgatorres dot org (Catalan)
www.fundacionolgatorres dot org (Spanish)
www.olgatorresfoundation dot org (English)
So what happened? I redesigned olgatorresfoundation on the 20th and the fundacionolgatorres on the 30th of May. In both cases, exactly two days later, the number of impressions on both dropped to a halt. Granted, we did not have the traffic of Microsoft, but a 90% decrease a disaster of incredible proportions for us.
My only real changes were cleaning up the old ineffective HTML to a cleaner form (mostly moving away from redundant table construction to a table-less view). Here is a before and after snapshot of what the change looks like:
Before: http://www.fundacioolgatorres.org/aparell_digestiu/introduccio/ (unchanged page in Catalan)
After: http://www.olgatorresfoundation.org/digestive_system/introduction/ (changed page in English)
Anybody has a clue to what just happened? Why should a normal, sane html improvement be punished and so dramatically? No URLs have been changed, neither have page names or descriptions.
Possible secondary question: If it is so that Google sees it as a major overhaul and decides to drop the pagerank sharply, does it come back to pre-change levels if the content "checks out" or will the page start over from scratch earning those pagerank points (which would mean that we would have to wait 6 months for the pages to recover to the level they had two weeks ago)?
(duplicated from productforums.google dot com/forum/#!category-topic/webmasters/crawling-indexing--ranking/YsnyX0JzOpY, hoping to reach a wider audience)
