According to Tarantino, Sonny Chiba's character, Hattori Hanzo, is meant to be the most recent descendant of his character(s) from the TV series "Hattori Hanzo: Kage no Gundan" (or "Shadow Warriors", as it's known in the US). The series was done in multiple various installments, and in each installment, Chiba would play the next Hanzo descendant.
Vivica A. Fox shooting through the cereal is a reference to the episode of the Simpsons called "Simpsoncalifragilisticexpiala-D'oh-cious," which features an episode of Itchy and Scratchy called Reservoir Cats (a parody of Resevoir Dogs), guest directed by Quentin Tarantino. In the cartoon, Tarantino appears and says "What I'm trying to say in this cartoon is that violence is everywhere in our society, y'know. It's, like, even in breakfast cereals, man."
In the opening credits it mentions the story is by "Q & U", this is Quentin Tarantino and Uma Thurman, the director and lead actress.
The yellow track suit that Uma Thurman wears during the tea house scene is a replica of the suit worn by Bruce Lee in the movie "Game of Death."
The real name of Uma Thurman's character (The Bride) is Beatrix according to Vernita Green. It can be surmised that her name is "bleeped out" in respect to nameless hero movies like Clint Eastwood's "Man With No Name" westerns or Robert Rodriguez's El Mariachi movies. The main characters all have nicknames, like The Bride, but their real names are never known.
The character Gogo was originally written as two characters: the twin Yubari sisters, Gogo and Yuki. Gogo had almost no lines and after her death at the hands of The Bride, Yuki would seek her out, only to be killed as well, in the "lost" chapter "Yuki's Revenge". All of Gogo's dialogue would have been spoken by Yuki. Tarantino references this lost character/scene in the first chapter of the movie; when The Bride is standing outside of Vernita Green's house, you can faintly hear an ice cream truck jingle. This was originally supposed to be Yuki, who stalked The Bride in an ice cream truck.