Think about what "decision tree" means..
You won't get much ( if any ) traffic for keywords that panda has decide don't fit what it thinks your site is..and how it decides is based upon many factors, both signals within your pages and in the pages of who you are liked to and who you link to.
This is why a group of pages can affect how your whole site ranks for keywords that you think it should ( and panda has decided that it should not )..and panda is learning by re-running the cross related data at intervals..and mixing it with the usual algo variants..
All this has been "blindingly" obvious from the start ..to any one who read either Mr Pandas work ..or the writings of some such as SEObythe sea..But almost without exception posters here and elsewhere got hung up on what was affecting their "ranking" based upon solely what was on their site.." how come I have all these backlinks and I still saw my rankings for "widget" fall"..
Or they got hung up on the guys name and their association with the word and thus spent their time posting and reading smart ass comments about "not very cuddly" etc..
Or deciding to rant about their perception of push to adwords as a forced way out ( because they couldn't see what criteria Panda was using ..or didn't want to see ..they were "entitled" to traffic as they had always had it ) and therefore that must be why in their opinion the addition known as Panda was run out.
He is a programmer..as most at the plex are ..many are also specialised mathematicians..and the plex loves automation..
Panda is attempting to automate by machine learning to replicate the "decisions" that humans made about what sites are "about"..into which "categories" they "fit"..
So sites that do not give very clear signals ..such as sites that sell product ..but also run adsense or ads..are not clear to users ..not the ones who Google used to test and set the criteria ..pre panda ..so they lost traffic..any site whose purpose and thus category or "brand" was not obvious was affected..and whether the site was set up with the intention of selling a product ..if many of its pages are running ads ..it gets put in the "ad site" category ..and maybe in the "MFA" category ..and gets dinged by another part of the concurrently running other algo ..
Site "topic" or "theme" or raison d'ętre..needs to be real clear ..so clear that it could be taken in at a glance..that has appeared to be the way that even manual appraisal has been done for years with Google..quick glance ..you are in ..or out ..account "shut" or re-instated..spam ..or not..ecommerce ..or info..first, fast impressions always counted for Google's "customer support"..or "assessors"..they tag 6 pages from a site as spammy ..your site looks like that site to panda ..it calls you a spammy site..'til it learns different..or maybe it got it right..
Its machine learning ..and sometimes just like any machine learning it will veer off at tangents for a while ..they get too "off target" , it gets tweaked back..so it knows that "ford" probably means you are looking for a "car" or a "car manufacturer" and not "how to cross a river without using a bridge"..
And Google put a lot of store in "smarts"..remember when they hired people by putting mathematical puzzles on bill boards..you got it right you might get hired ..they didn't concern themselves with how many wrecks they may have caused because people were distracted..because the "smart ones" could figure it out instantly and keep driving safely, nor did they worry about if the boards were standing on pylons over the top of some homeless person's cardboard box home..
They wanted "smart"..that is what counts to Google..( and "fast thinkers".. because they apparently think that Larry perceives things like pages loading unusually fast ..he doesn't..two hundred milliseconds is nothing special..unless the rest are "stoners" )..thousands of sites might wither and die due to Panda? ..
So..there will be more to replace them..and they will ( eventually because it has to learn ..and Google take a long view..so "learning " might take a few years even ) be more targeted , more focused, and faster ( apparently no-one at the plex has the "balls" to tell Larry that it is his adsense and or analytics code that slows down many pages ..or maybe they do and he says ..well they'll ( the webmasters ) have to figure out a way to make the rest of the pages faster to make up for it ..or that newer CPUs will take care of it ..it is all javascript ;-) so mainly "bottlenecks" are put down to "client side" )..but more sites and more pages will come along to replace those that wither through lack of traffic..
That is like "evolution" for the web ..survival of the fittest..the dominant in their "niche" ..not the blackest, nor the spammiest..although both of those may from time to time benefit from the combination of panda and the other algo variables as the machine "learns"..meanwhile ..why should they care if some don't survive..and why should they cry if some sites decide to try to keep their place in the sun and their traffic via adwords..
Even when they compete in verticals with their own products ..in their thoughts and philosophy they are convinced, they are sure they can do it better, ( might be the case ..or not )..and the revenue can only make them stronger, and thus better equipped to do what they want to do..you, as adults "know" what is best for your children, what is best for kids in general, in the long run..because you are brighter and consider yourselves to know more than your kids..you are more intelligent than your pets..you have learned complex things like websites and economics and marketing and maybe even a little code..
You feel , nay ""know that you are smarter than many of the people who you interact with daily..on and off the web ..and those who visit your sites..
The people at Google ( and if the truth be known, at the other search engines and IT companies ) "feel" and "know" that feeling of knowing more and better and what is best ..in "spades"..
They will only "bend" a little, if they think either they have miscalculated or that you are as smart or smarter than they..complaining is not going to be taken as a sign of either..
And they may well be right..and their "way" will probably prevail..
There is plenty of "data" already available there in front of you ( more is not needed )..you need to look at it properly..from the point of view of the programmers ( Mr Panda included ) in the plex..it, "panda" is doing more or less what it was intended to do ..and learning as it goes..and deciding..always deciding..
[edited by: Leosghost at 3:54 am (utc) on Oct 18, 2011]