Another important question you need to ask is if their budget or revenue criterion matches the range for your product or service offering. If your product plays to the high end of the market and your lead’s budget is low, this just won’t work. So it is better to know the answer to this now rather than in the later stages once you’ve invested more time in the lead.
Less than 5% of all purely online businesses (i.e. business that have no traditional, physical counterpart) ever actually make any money. It's hard to draw a decent living from the Internet, but because it is easy to setup, the allure is great enough to keep people trying. If you are to be successful it is imperative that you avoid the mistake of not being disciplined in your approach.