I don't know if I buy that "formula".
I think a more accurate measure is based on current income and growth curves of the site.
This is an impossible question to answer in the general, though. http://www.very-cool-stuff.com/ubb/smile.gif
btw, My opinion on iLinktrade is that it's not worth very much. They have no traffic. That's where the money is. I can throw together "yahoo2", but without the traffic, it's worth nothing.