Many people are likely to be unaware exactly what their website is worth. This is mostly down to the fact that the money it earns you and what it is actually worth can have very little correlation. After all, social networking sites can sell for hundreds of thousands of dollars, and even into the billions, and it is unlikely that any of these sites have actually been turning over this kind of profit year on year.
This means that what a website earns you and what it could be worth are likely to be very different, especially if you have a very good website that isn’t currently reaching it’s potential. Whilst web stats will indeed be important to a buyer, if you can show that you have had a great deal of interest without actually marketing the site in the way it should be marketed, a buyer may well see just how much potential there could be in a site should a company take over that has the time to work on it in much greater detail.
Visiting a site where you can buy and sell websites will be a great way to see how much similar sites are going for, and you may well find that a site that brings in a certain revenue in a year with a great deal of work involved could actually be worth a similar amount to you in a one-off sale, without you having to lift a finger.
Of course, some sites will be worth less when sold than they are actually earning an individual and therefore it is worth taking this into account too before you decide to put up any of your web sites for sale.
There are of course ways to increase the value of a site. If the name of the site is likely to seem old hat very soon (for instance, if the URL includes a date or a modern cultural reference), changing the name will help you to get far more money (so long as you direct people to the new URL for a significant period before you sell).