For one reason only : Adwords
http://www.google.com/webhp?complete=1&hl=en
All the popular keywords will get more searches and the prices of the bids will skyrocket.
The competition will be focused on the more popular searches.
This means that the "obscure" searches will vanish and get less attention.
For anyone using google adwords, enjoy.
There's always a business decision behind every move. Of course the SEO will think that it's because Google loves them.
Fools.
