After the recent hype about contextually targeted ads on digg . I noticed that digg.com uses the same technology for delivering ads. Digg being a high traffic site I decided to do a search for revenue of digg from using it :).
I did not find the revenue for digg but I clicked on the first result on the page see it below. See the ad served at the top of the page :D
LOL competitors ad served by competitors :). I guess they forgot about filtering their own competitors out :)