Here's a blog post by a real estate webmaster involved in a nationwide reciprocal link penalization [activerain.com] in 2007. It's an example of how not to exchange links. This post is an important one because afaik it preceded many other posts and discussions that described this important event. The penalization of a large group of real estate agents trading links nationwide was a big deal when it happened and I feel that members who aren't aware of this event should be made aware of it so that they understand the historical underpinnings of why certain things are done in a certain manner. As already mentioned above, nothing wrong with trading links with a few reputable good quality websites. The above blog post is about how not to do it.