Afro Samurai author Takashi Okazaki talks about creating the series, how it became a multimedia franchise, and how Samuel L. Jackson got involved. Also includes comments by director Fuminori Kizaki.
The story of how the anime got started because of a toy on a producer’s desk seems like another silly gonzo story from an ever-growing pile, but it’s likely not the only reason. Still, it is an interesting starting point.
Animetics 
Afro Samurai seemed to attract the attention of people who were not even anime fans. Shame because it wasn’t all that great. There are much better samurari animes out there.
Yeah, popularity for bigger hits is always kinda arbitrary. There’s a nebulous concept of “cool” out there which really seems to determine what becomes mainstream in the US that I’m not a huge fan of.