One of my secretly long-lived dreams is to work on Saturday Night Live (SNL). A fan for years, I have been slightly disappointed with the show's recent seasons. Unfortunately, the show does not consume the spark that it used to have but I still watch it because of the brand. SNL has aired on television every year since 1975! It's a classic. Even Ben and Jerry's ice cream company came out with a new flavor called Schweddy Balls, named after a SNL skit featuring Alec Baldwin as Pete Schweddy. http://brandchannel.com/home/post/2011/09/07/Ben-Jerrys-Schweddy-Balls.aspx
I recently finished former SNL writer/cast member, Tina Fey's book Bossypants. In her book, she talks about the hectic-fun-stressful-memorable environment when working for SNL. One of the highlights of her career was portraying Sarah Palin, who was running for Republican Vice President at the time. During one of the late-night episodes, Palin was featured in one of the sketches. You would wonder why someone like Palin who got mocked so frequently on the show would want to show her face around the writers and crew after all the things they said about her.
The answer: publicity. This is the reason for every SNL host. They are usually coming out with a movie or they are "what's hot" in the tabloids. Not only is SNL helping the celebrity promote his or her movie/brand and in some cases giving the host an opportunity to clear the air over public scandals, SNL is also crossing fingers hoping that ratings will go up based on the choice of host. It is all strategic.