There are plenty of people out there touting the benefits of 3 way links systems.  However, what is it that makes these systems work so much better than your typical two way reciprocal link exchanges?

One reason is that these links are built over time.  So many reciprocal link exchanges that have existed in the past have sent all the links to your website all at once.  While that worked great for search engines like Yahoo and MSN, it was a death sentence for those wanting to rank well in Google. 

Google is smart enough to realize that getting all of those links at one time is not natural and that the person is likely trying to game the system.  So when your links are built up slowly over the course of two months at a varying rate of speed, then you really start to seem some benefits.