With the help of the free PDF from diveintogreasemonkey.org, learning and finishing my first app only took me an hour. I’ve not finished the book yet, and I don’t have to.
The first one is simple, just replacing some keyword in the web page. And I finished my second app this morning. It can help me fill the form automatically, quite useful when I need to bulk-register lots of account.
It’s an itch-scratching product, with very flat learning curve.