By Kim Westerman
How is it that there are so many variations on the theme of flour, water, yeast, tomatoes and cheese? What makes pizza "authentic?" This food with Italian origins is now an American staple, and there are more styles than you can shake a stick at, the most common in the Bay Area being traditional Italian and Californian.
The line between the two is perhaps a faint one, but it isn't arbitrary. Italian-style pizzas, first and foremost, aren't overloaded with ingredients, as many Cali-style pizzas tend to be. In Italy, there are no "meat-lover's" or "everything" options, and the minimalist approach is also honored with modest proportions of sauce and cheese.
Source: http://ww2.kqed.org/