Producing any information product is almost entirely an exercise in marketing. Everything from the topic you choose, to how you position it, to the copywriting strategy you use to sell it boils down to figuring out what people are willing, and even driven, to pay for.
As more people begin to realize that blogging for ad dollars and other free content strategies might not be the best way to make money online, I’m getting more and more questions related to writing and selling ebooks.
The venerable PDF seems to come to mind when people consider developing a information product and selling ebooks, but it’s often the least useful and has the lowest perceived value—especially when you want to charge for it. As far as ebooks go, the question you have to ask is whether or not the ebook is the format you should be using at all.