Think about how many queries are in total? First, think of how many sites are in Google’s index. According to http://www.worldwidewebsize.com/ Google’s index is approximately 37 billion pages. On all those pages combined, how many unique words exist?
According to Oxforddictionaires.com “If distinct senses were counted, the total (number of words) would probably approach three quarters of a million.”
It’s pretty unlikely that over 700,000 English words would be used online, however it is quite possible when there are over 37 billion pages online.
With the volume of the number words understood, how many unique combinations of those words exist? Let’s be somewhat conservative. A normal literate person should know somewhere between 2,000 and 4,000 words in their first language.
When you calculate for only 2 word permutations of a literate person’s vocabulary size of 4,000 words, you get a total of 7,998,000 total permutations. Just imagine how many possible 3 word permutations there are, and the numbers become staggering!
With this insight, I think it’s safe to assume that all the keywords affected by Panda 3.8 just happen to be all the money words in the Adwords database. Think about it. If you were Google would you worry about all the possible queries, or just the ones that could make you more money?