Dr. Horrible's Sing-Along Blog took the Internet by storm during the WGA strike, and in addition to being heavily downloaded, the CD and DVD sales have been exceptional. But ever since the third part of the series aired, fans have wondered what next? Well, Joss Whedon isn't saying - yet - but he did tell SCI FI Wire that more would be coming.

"It is my intention that we will see more of young Billy and his horrible schemes, and I have a very specific idea of what that's going to be, but until I'm sure how I can roll it out, I will say nothing except that I'm definitely pursuing that," Whedon promised.

Whedon also says that he wants to do more with Internet based projects, although those may not specifically be Dr. Horrible.

"I mean, there are two things that happened. There was Dr. Horrible itself, and there was the Internet sort of event, and I'm pursuing both of those kind of separately, in the sense that I want to tell a Dr. Horrible story, but I also want to continue trying new things on the Internet," Whedon added, somewhat cryptically. "And it might not be Dr. Horrible, just because I want to keep it fresh. I don't want to just do the same thing because I did it successfully once. So ... it feels like two very exciting avenues have been opened up by that experience."

Dr. Horrible's Sing-Along Blog was a three-part web series created by Joss Whedon and his brothers, Zack and Jed. It stars Neil Patrick-Harris as Dr. Horrible, a down-on-his luck supervillain, Nathan Fillion as his nemesis, Captain Hammer, and Felicia Day as the girl of his dreams, Penny. Originally available for viewing on the web at www.DrHorrible.com, you can now download it on iTunes. The series is also available on DVD, with a soundtrack CD also available.