From a Betty Boop Fan Site:

Betty Boop started out in the early 1930's as a dog character, primarily as the love interest of a dog character named Bimbo, in the Talkartoons series produced by Dave & Max Fleischer. She was featured in several cartoons as this dog character through 1930. It didn't take long for Betty to surpass Bimbo in popularity, and become the main character in the cartoons. (From: Starring Bimbo, featuring Betty, To: Starring Betty, featuring Bimbo.) In many of her cartoons Bimbo was portrayed either as her boyfriend, or at least a wanna-be boyfriend. As Betty's popularity grew, she went through a transformation, losing her dog characteristics. (Although her dog ears hung on for a little while, before becoming earrings) Before long she became the cute and sexy character that we Betty Boop fans have grown to love. Her body was modeled after Mae West, and her voice was done by Mae Questal. There were more then one hundred Betty Boop cartoons produced, including, "Betty Boop for President" (1932), "Bamboo Isle" (1932), and "Riding the Rails" (1938), which even received an Oscar nomination. Trick or Treat One of my favorite characters in her cartoons is Grampy, the eccentric inventor who, after putting on his thinking cap, seems to be able to solve any problem. Grampy's way of doing things, was always fun, and to say the least, unique. Another character that showed up occasionally was Koko the clown, although he usually appeared as nothing more then an "extra" in Betty's cartoons. And then there's Pudgy, Betty's little dog . He's featured in many of her cartoons, in fact there seem to be a couple of cartoons that he is the primary character. Some of my favorite Betty Boop cartoons include: "Poor Cinderella" (1934), "A Language all my Own" (1935), and "Betty Boop and the Little King" (1936). Betty's popularity began to decline after her creators were forced to "clean her up" under the Hays Code. Gone were the short little skirts with her garter showing. Her hemline moved down to her knees, and her character took on more of a school teacher persona. Since it was the "cute" and "sexy" characteristics that made Betty popular, eliminating them meant the beginning of the end of Betty's popularity. During her prime, it was not uncommon to see big name musical guests making appearances in her cartoons. Some of these were: "I'll be glad when you're Dead, You Rascal You" (1932), featuring Louis Armstrong, "Minnie the Moocher" (1932), featuring Cab Calloway, and one of my favorites "Snow White" (1933) featuring Cab Calloway doing the song A skiing we will go... "Saint James Infirmary Blues". In the 1930's, Betty Boop was made into dolls, toys, and other collectibles. Her popularity declined for several decades, but then, in the 1980's she began to become popular again. Now, as she becomes more popular, there are many products and collectables available. Some of the items I have are dolls, ceramics, T-shirts, posters, watches,and more. Almost anything you can think of, is now available. I think that Betty is as popular now, as she has ever been.