I'd rather pay for each HowTo that I create or let them run an ad in middle of each presentation. This is seriously cool and has awesome possibilities but I'd hope they would reconsider their business model.
we are considering enterprise version, private flows as well as ads for monetization.
I'm interested in adding something this to my webapp, but I'd need to see what it looks like first and I don't want to have to install the extension. I also don't want my users to have to install the extension.
I'm also looking into alternative projects like Joyride from ZURB  and Guiders from Optimizely .
you can see flows on that app here: - http://www.searchenabler.com/faqs/
Anyways, I probably won't add it to my project because, while I think it could be useful, I don't really like how it looks and I think the error handling could be improved. For example, when I clicked the login button in the example you sent the guider just disappeared.