Musicians have always struggled with whether licensing their music or becoming a spokesperson for a brand will affect the relationship they have with their fans. Some artists have been able to reap the benefits of ad partnerships and use it to grow a dedicated audience. Others have spread themselves to the point of becoming a musical plague.We present case-and-point studies of 12 musicians or bands who have become household names—and whether their choices to work with advertisers has affected their place in music history. —MUSICIANS WHO SOLD OUT AND WONSnoop Dogg / Snoop LionNo one has been able to retain cred and sell his talents to almost every company like the D-O-double G. Snoop has promoted everything from Star Wars products for Adidas to ultra-caffeinated Pepsi Max. He even got away with the horribly punny Pocket Like It’s Hot and You Got What I Eat, both for Hot Pockets. He can do no wrong.MadonnaDon’t forget that the pop queen sought sponsorship from Pepsi for her classic single “Like a Prayer.” That relationship burned to the ground. (No pun intended.) Despite that fiasco, she’s still in advertisers’ good graces and has worked with BMW and Gap to name a couple.Impressively, she’s still retained her rebel persona. Just a few years back, ABC reportedly asked her to tone down the sexual content of a perfume commercial. Not bad for being a Material Girl in her 50s.U2The Irish rockers sponsored a red iPod and teamed up with Bank of America both to unveil their track “Invisible” while supporting a worthy cause, fighting HIV/AIDS with the (RED) campaign. But, they haven’t lost their ability to sell out stadiums.Dr. DreThere probably hasn’t been an album as anticipated as Detox, which has reportedly been in the works since 2001.But no one has accused Dre of not keeping busy. In addition to producing acts like Eminem, Kendrick Lamar, and 50 Cent, recently his most well-known contribution to the music world has been touting Beats by Dre. Instead of accusing Dre of working on electronics instead of getting to the studio, fans are rocking the multi-colored headphones as a fashion accessory.Bob DylanWhen the iconic rock legend decided to do a Super Bowl ad for Chrysler, many listeners accused him of selling out.However, they seem to have forgotten that Dylan has appeared in past spots for Pepsi, Apple and Victoria’s Secret, while licensing his music to many more companies. His long career has survived these campaigns, and it’s highly unlikely that Dylan fans will stop listening anytime soon.MetallicaThe band complains about how it isn't making enough money because people are listening to its music for free. They've licensed their music to Guitar Hero, which is basically musical instruments for people who have very little musical talent. Lars collects fine art.Fans still worship them as metal, counter culture gods.