Dr. Horrible's Sing-Along Blog pays its crew and all its bills! Joss
says so.
http://whedonesque.com/comments/18243#270186

Featuring "Commentary! The Musical" "It has nearly twice as much
music as Dr. Horrible itself -- since you can't really talk that much
during a commentary musical or it sounds like a regular commentary.
(Which we also have, with the stars and writers, plus making-of's,
ELE applications, and ... )"

http://news.tubefilter.tv/
http://news.tubefilter.tv/2008/11/29/dr-horrible-dvd-ships-december-
19th-pre-orders-booming/

Pre-Order Your Dr. Horrible DVD NOW!!
http://www.amazon.com/dp/B001M5UDGS

Tell your friends! Unless, of course, you are buying it for them for
Christmas!

Neil Patrick Harris as Dr. Horrible
Nathan Fillion as Captain Hammer
Felicia Day as Penny

Directed by Joss Whedon