rogerd - 9:16 pm on Mar 4, 2007 (gmt 0)

I have to believe that massive link exchange schemes that create similar themed pages on many different sites WOULD be detectable by Google, both algorithmically and in the course of manual checking. Either way, once a network is discovered, those link pages would be devalued.

I think the experiment is interesting, but I don't think 4K automatically exchanged links that popped up in the course of a few weeks can be directly compared to getting links from 4K individual site over the course of a year or more. (Not that one could get that many, or that it would be worth the effort.)

Your point about purchased links from non-links pages is well taken - even though Google would like to prevent link buying, it's pretty hard to catch algorithmically.