Looking at the Author, Reviews and the Table of Contents is probably a better heuristic.
That said, for things that aren't books, a marketing department that is complete dogshit might point to an opportunity. Berkshire Hathaway doesn't have great marketing. It doesn't need to.
If you go on Alibaba and find a merchant that has a great prospectus and a broad range of products, that's most likely a reseller. That means they take their share of the pie, and if you try to get something manufactured, you'll be working through a proxy. Better to find their manufacturer instead.
That said, for things that aren't books, a marketing department that is complete dogshit might point to an opportunity. Berkshire Hathaway doesn't have great marketing. It doesn't need to.
If you go on Alibaba and find a merchant that has a great prospectus and a broad range of products, that's most likely a reseller. That means they take their share of the pie, and if you try to get something manufactured, you'll be working through a proxy. Better to find their manufacturer instead.