For example, a textbook has both for-profit and educational aspects to its use. The critical test is the intent, not the fact, of profit. Some book reviews, such as those in the New York Review of Books, quote extensively from the books under review. The review itself is usually commercial and for-profit. A publisher will almost always allow a review as fair use, because even negative publicity is considered good.
Parodies create another set of problems.
Prior to Campbell, the publishing industry assumed that a commercial parody could never be fair use. The Smothers Brothers had some problems with this policy. On the other hand, Weird Al Yankovic always gets permission for his parodies. As we'll see in question 8, this is the most important factor in determining whether a copyright holder really cares about a parody, or any other borderline fair use. Remember that copyright is in the expression, not in any underlying facts.