Those figures fit with what I remember about ad revenue. If I remember right, it's normal for around 2% of hits to convert into an ad click. If we pair that with a $0.50 mean earning-per-click (memory and a cursory search of the Internet say this is reasonable), we get:
$0.50 * (1.5 million * 2%) = $15,000/mo.
That leaves some leeway for Crranky to have worse performance and still hit his quoted $10,000/mo.