The answer to this question is a little complicated. On the one hand, Dr.
Horrible’s Sing-Along Blog does have some musical elements in it. For example, there are songs featured prominently in the show, and characters often sing and dance along with the music.
On the other hand, Dr. Horrible’s Sing-Along Blog is not a traditional musical.
It does not have a linear plot, and it does not follow traditional musical conventions such as staging and performance art. As a result, it is difficult to say whether or not the show is actually a musical in the traditional sense – that is, if it has been specifically designed to be viewed as such by its audience.
Ultimately, this question is subjective and can be difficult to answer definitively. While Dr.
Horrible’s Sing-Along Blog may not be strictly a musical in the traditional sense, it does have some musical elements present, which may make some viewers consider it to be one.