Looks like the owner of this domain is probably well-versed in the value of it; it's typical of the portals that are owned by rich domainers who buy them and plonk ppc links on them. So I won't give you a valuation of it as he's probably well aware it's into the tens and possibly hundreds of k's.
I think you were more interested in finding out how much traffic that site would actually bring to YOU, if you had your content on it/referred to by it?
If I'm reading that correctly, then the best way to tell this is to ask him to provide you with two stats:
1. How many unique views he gets each month, so you see how many people are actually visiting his site.
2. How often they click on the links (he should have some counter available to you) so you can see what kind of traffic the links (and you) are getting.
Another important thing is to, if you can, find out which kind of links get the most visitors through his site... if your content is similar to that, it's another good sign.
This thread probably would have been best placed in the 'discussion' forum rather than this appraisal forum, since you were asking for information unrelated to getting an appraisal on a name you own...