Of course, the most important thing (at least for us) is the effect this trend has on students. Co-taught classes are popular, for the most part, because they are better than other courses. They have better teaching, more varied viewpoints and provide valuable mentoring for junior faculty. However, students should not be drawn in by classes co-taught by multiple faculty "stars". These classes can be poorly prepared and poorly taught, with the professors relying simply on their star power to draw in students.

As Williamson said, co-taught classes don't, "give any Faculty member the license to slack off."

If, by add-drop deadline, you find that your co-taught class, despite the high-powered professors and catchy title, isn't living up to your expectations, if you find that the professors are talking more to each other than to the audience, and that the lecture resembles one of those endless abstract discussions you have with your roommates late at night, you may want to reconsider. After all, those discussions are always more fun when you get to participate. Professors should become stars for their teaching ability, not for their publications or pontifications. Make sure you get your money's worth.