[devmonk]

Some ideas:

- Bill on a per-use basis

- Hours of usage are prepaid like calling cards

- Ads

- Selling data collected to others (and it doesn't even have to be personally identifying customer info. I worked for a company that did speed tests and at one point a company in another country that knew of our speed tests wanted to buy our speed test result data. We never sold it, but sometimes offers come to you!)

- Donations (via paypal, etc.)

Can it generate enough money from Ads? Not as well as it used to be able to, but yes it is possible. Is it likely without much effort? Depends on amount and kind of site traffic and content of the Ads.

You need to have confidence in what product or service you are selling, though, and have a potential/real customer feedback loop setup from the beginning. You shouldn't rely on Ads alone. If no one is coming to your site, they won't click on the Ads.