310-533-9145 Spider Juice Technologies - Coach T - a human will answer
Percentage of U.S. clicks by number of keywords
Subject October 2009 November 2009 Month-over-month percentage change
One word 24.03% 24.13% 0%
Two words 23.13% 23.14% 0%
Three words 20.53% 20.37% -1%
four words 13.83% 13.84% 0%
Five words 8.13% 8.13% 0%
Six words 4.42% 4.43% 0%
Seven words 2.43% 2.43% 0%
Eight or more words 3.49% 3.54% 1%
Note: Data is based on four-week rolling periods (ending Nov.
28, 2009, and Oct. 31, 2009) from the
Hitwise sample of 10 million U.S.
Internet users.

It seems one to three keywords still rules search. Typically, keywords become longtail as they increase in number.