Sorry if this is incorrect but wouldn't a better term be long term capital gains rates? Short term capital gains are taxed at ordinary income rates but they're still capital gains.
Do you have more information on how that course is going to look like? Are those going to be video tutorials, or some degree of interactivity like on Coursera?
IkmoIkmo got this spot on in his/her comment.
Biggest two mistakes people are making in this thread:
1. $100k was revenue, not profit.
2. I get capital gains rates on the sale, versus ordinary income rates.
(If you didn't know about #2 you should probably sign up for my accounting and tax course for freelancers and entrepreneurs: http://trevormckendrick.com/accounting-course-for-entreprene...)