If you include Apple iTunes Music Store songs in your iMovie/iPhoto slideshows, you're boned if you try to send the slideshows to friends.
"When you purchase a song from the iTunes Music Store and you use that song to create a slideshow in iPhoto or use it as an audio track in a movie you create in iMovie, you would expect that your movies & slideshows would work when you email them to other people.
"But no! Not only does Apple NOT let your recipients view your iMovie movies or your iPhoto slideshows, but the worst part about it is that YOU DO NOT receive a warning when creating these slideshows or movies in iPhoto or iMovie.
"Imagine burning your slideshow or movie onto a CD and distributing them to a bunch of people, only to be embarrassed later that none of your recipients can actually view the movie."
Users receive the message "This computer is not authorized to play the file nameofmovie.mov."
(Thanks, Matt!)
