His blog posts regularly make the front page here. Most recently http://news.ycombinator.com/item?id=1344062
He has stated revenue primarily comes from app store, where he sells "A lot of small cheap apps.", and also that last month sales came close to 40k.
cubeofm.com lists one "Art you should know" app and a desktop appstore stats app. iTunes shows no other apps by that apps author. So, can someone point me to some of the "small cheap apps" he sells?