Wikisimpsons - The Simpsons Wiki
Malibu Stacy is a plastic doll that is manufactured within Springfield. It is the most popular doll in Springfield. Stacy is Lisa Simpson's favorite doll, despite some moral issues she has had with the attitudes it promotes.
Malibu Stacy was first created in 1959, when Stacy Lovell designed a doll that you could also eat. The first release of the doll was unsuccessful due to the doll's main ingredient dried onion meal, but the design of the doll was lauded, and so a plastic version was released soon after. Once that happened, Malibu Stacy became incredibly successful.
Stacy Lavelle was forced out of the company in 1974, stating that her thinking wasn't "cost effective". Lavelle herself believes that the more significant reason for her dismissal is her funneling of money to the Viet Cong. Since then, she has had no real control over the company she created.
Despite its popularity amongst the girls of Springfield, Malibu Stacy is also shown to be rather sexist in what it represents and teaches, ever since its debut (Marge Simpson was shown to have being somewhat influenced by it in her childhood, quoting that all of the controversy would be fine after forgetting it over ice cream).
When 'Talking Malibu Stacy' dolls were introduced, pulling a string on the doll's back provided typically vapid catchphrases that were demeaning to women (such as "Don't ask me, I'm just a girl!"). Lisa fronted an effort to produce a competing doll called "Lisa Lionheart", which would act as a more positive female role model. Its sales were disappointingly low, being thwarted by the simultaneous release of "Malibu Stacy With New Hat".
Malibu Stacy is the most popular doll in Springfield, and her biggest fan is Waylon Smithers, Jr.. On several occasions, Smithers is said to own the largest collection of Malibu Stacy dolls and accessories in Springfield. Smithers also publishes a newsletter for fellow Malibu Stacy fans, and has written and produced a musical based on Malibu Stacy.
 Lisa Lionheart
Lisa and Stacy Lovell team up to create a rival "Lisa Lionheart" doll to try to stop the production of Malibu Stacy and to act as a better women's role model. The doll, which says several intelligent sayings, is only bought by one girl at the end of the episode.