Ask for proof of revenue for the last few months. Basically you want to know if the site has been earning revenue for some time, or just in the last month or two.
Consider the websites sales proposition, is it a good one, is the site offering a good product or service for sale?
Is the seller reputable, check their forum feedback (presuming you're buying the site through a forum)?
How many customers does the site have? If they are getting all their revenue from a small number of customers this might be harder for a new owner to sustain.
Bookmarks