Discussions regarding how to make money with an open source business model pop up with increasing regularity and that’s good because it’s a topic that needs debate.  But I would bet that we’re going to see more and more articles like this one, that basically start to point out the real costs of being a "closed source" business model.  If your users are sophisticated enough to hack your product to get what they’re looking for, is it more economic to just design it so they can get it easily or to continually try to fend them off with counter measures?  I personally think the answer is obvious.  Just look at the state of the music biz.  Users will get what they want one way or another.  The advantages of being open outweigh the costs of being closed.

UPDATE – another good article.