According to the BusinessWeek article, "Why Yahoo's Panama Won't Be Enough", Google is making an average of 20 cents per search:
Using data on total search queries, released by comScore, Caris & Co. analyst Tim Boyd estimates that Yahoo made on average between 10 cents and 11 cents per search in 2006, bringing in a total of $1.61 billion for the first nine months of the year.
Google, meanwhile, makes between 19 cents and 21 cents per search. As a result, it made an estimated $4.99 billion during the same period.
Wow, is it just me or does that seem really high? According to my Google Search History, I'm averaging about 30 searches per day. That means Google is making about $6 a day from my surfing.
[via Geeking with Greg]