This brings up a point I've been wanting to discuss for some time.
In reading through the stickies here and articles elsewhere, I often see "link exchanges" denounced as a useless or even harmful technique.
By "link exchanges", do you mean irrelevant link exchanges, such as those brokered by third-party websites with the sole end of increasing PageRank? Or do you mean all 2-way linking, even with relevant sites? If the former, I understand. If the latter, I remain puzzled as to how certain types of sites would otherwise receive any volume of incoming links?
I can see how content-heavy sites such as blogs can attract links naturally; they add value to the linking sites. But how do you get an appreciable number of one-way inbound links for a strictly commercial site which exists only to sell something? Not every website can provide a large amount of broadly interesting information that other people would want to link to, but every website certainly needs inbound links.