You may have noticed that I have added some "Ads by Google" to the site. This is an experiment: Given the traffic on this blog, I don't expect to make any money from it-Google only send me a cheque if the fractions of pennies per click add up to more than $100USD; in the likely event that the balance never gets that high (it's zero cents now), I'll never receive anything. I guess I am effectively providing free advertising- and subsidizing Google at the same time!
I'm curious about the business model of pay-per-click, so what better way to find about about it than with a real-world experiment!
By the way, I have no control over the ads that get posted. I can block individual ads that seem unsuitable, but I have better things to spend my time on.... like research and preparing lectures!