Jay Z is building a range of businesses just on the strength of his brand. Lady Gaga has formed really interesting partnerships. Justin Bieber and his manager Scooter Braun are investing in a number of different companies and also promoting them in many ways.
If you are the record label who owns Lady Gaga, and you have a new artist coming up, you can say, 'Let's have the artist play just before Gaga.' Now you've exposed the huge Gaga audience to the new artist. It's similar to showing a trailer before a movie. The hit creates a hit.