I disagree with this thread. It's quite unfair to push Max Klein that he will reveal his business niches. His specific business details are unrelated to the quality of his business, which are (still) valuable even without knowing the specifics. Would you like to share your specific niches with the HN-Crowd, full of highly productive programmers?? I cannot ignore the feeling that the purpose of questioning the authenticity of Max Klein and his blog posts is to expose his niches.