From the interview he linked to: "Here’s the data that I do have: as of today (April 12, 2009) I have sold to 3798 customers for a total of $469,048 in sales. Sales keep growing steadily: the last 7 weeks have all been over $20,000, with a record $35k week for the first week of April. We are averaging around 200 new customers per week right now"

He says he's making enough to pay a year's salary to everyone in the company each month.

3 employees, let's say 30,000 euros (40,000 USD) per employee per year (data from http://www.payscale.com/research/IT/Country=Italy/Salary/sho... assuming he pays everyone as Project Manager, could be lower). That would be over 100,000 USD per month in revenues.