We all know Search Engine Optimization is a difficult business. Sometime we have a tendency to rank well on one engine for a specific keyphrase and assume that every one search engines can like our pages, and hence we’ll rank well for that keyphrase on variety of engines. sadly this can be rarely the case. All the most important search engines differ somewhat, thus what is get you ranked high on one engine may very well facilitate to lower your ranking on another engine.
It just because of decision that most of them not giving useful information on his sites. All of them uses tools in early days to change SEO (Google Analytics, Webmaster Tools, Gmail, Places). And frankly i can say that its not only because of google panda updates.
Now, the main question reason for headaches: How google will do all these changes?
Definition of SEO, Google’s guidelines:
Search engine optimization is about getting your site the best when it comes to visibility in search engines and your who ever visit your site that are your end users.