caribguy - 10:02 am on Mar 14, 2010 (gmt 0)
I tend to agree with JS: the amount of cash flow that the site will generate is key (what comes in minus what goes out). Etceteris paribus (all else being equal).
Next, look at exclusivity and barriers to entry: if you have agreements with suppliers, content providers, etc that nobody else can match, you might be able to get a premium price.
The owner's income as a standalone factor is not very relevant. The replacement cost is more important. If the site makes 500K in sales, how much is the cost of goods sold? That's a factor that is most difficult to influence...