Why do you figure overhead would be anywhere near 90%? It sounds like he's basically automatically scraping this info, and it doesn't need to be done at any particularly fast rate. He's probably leasing a single dedicated server for a few hundred dollars a month and working from home. I expect his overhead is near zero.

I think he was just being conservative to make a point, that EVEN at 90% he'd be making a LOT of money.

True. I just figured it was unnecessarily conservative. He said, "Overheads would be significant," which I don't think is actually true. I agree with the general principle that it's a lot of money.

What @personjerry said. His accountant must loose his mind.

In my experience, hosting is a lot more expensive than everyone thinks. That being said, choose a number - 40%, 60%, 90%.

I've never seen a business that generates THAT much revenue with such low overheads. Awesome business!

My experience has been different I guess. I run a small web-based business serving around 50,000 visitors a day. We don't do anything particularly bandwidth-intensive, but we spend less than $500/month on our server and bandwidth.

This guy's traffic would be considerably lower than ours I would think. Most of his resources are going to be going to the scanning effort. But that can run at a continuous rate around the clock, which is the most efficient way to utilize resources. And it doesn't need to be done completely quickly: it looks like he'd be fine completing a full scan in under a month. That shouldn't require particularly high-powered hardware.

So, I can't imagine this guy could possibly be spending more then $100k/month on hosting. Honestly I would be surprised if it was more than $10k. I was just trying to clear up what I saw as a misconception.