WebProNews reports on a post from Microsoft on link exchanges and how sites use them to gather link popularity. The question posed was whether or not link exchanges and link exchanging is a black hat tactic or not.
The first issue is to determine whether or not link exchanges are a serious threat to rankings. In the big picture link exchanges are no worse than paid revues. The search engines may penalize you but they are not considered black hat.
There is a list of some of the types of activities considered to be black hat on the WebProNews post. However as the post states:
It may not have as much of an effect on your rankings as it once did anyway, but I think I’m gong to have to go with Tamar on dubbing link exchanges as black hat being a little overboard.
Long term, links in themselves will become devalued anyway. They have not been a reliable guide to a pages true worth. Should you use a link exchange? Probably not. Should you exchange links? If there is something to be gained, and it is with a site in your own niche, most definately.