[oldcynic]

I would too for a technical book or course, to a point. Mainly as so many have managed to successfully sell garbage. ;)

A refund policy and giving away a couple of random lessons or chapters should cover credibility there. Some months blogging in that niche and some reasonably written code over on github should be enough background for casual searching. Build the rest as you go. I don't think it's too hard to stand apart from the Internet Marketer types.

You probably don't need much background for a $29 ebook or video course to sell, you probably do for a $1,999 on site course.