John Markoff and G. Pascal Zachary of The New York Times writes in "In Searching the Web, Google Finds Riches" (registration required) about Googles AdWords™ paid advertising feature which is infinitely better than any banner advertising you could ever get, since it presents a link that is somewhat relevant to what the user is thinking of right now. Relevant advertising — who would've thought people would like that.
Along the way they reveal that Google use a serverfarm of 54,000 servers with nearly twice as many CPUs in them. I would really like to know what kind of system they've built to manage that many machines. I'd love to work there.
Curiously the journalists also touch upon the dangers of having one third of all internet searches (150 million according to google, 200 million according to the article) going through one private company, which is the first time I've seen anybody else talk about it. And I've only thought about it in the privacy of my own skull, so I really can't take any credit.