I just discovered this! The Joker Blogs, which is a pretty cool idea for a webseries - featuring the Joker after his capture in The Dark Knight as he undergoes therapy with Dr. Harleen Quinzel.
A clever idea, a built-in audience, and an premise that allows for a low budget. That's pretty much a recipe for web series success.
I'm told subsequent episodes do a solid job of weaving in details from the movie and comic book continuities.