However, Builtwith is selling some plans which also include SEO related features like keyword reports. I understand that some might pay for latter but there is even more competition in that space.
What I don't get: Who should pay for your stuff? It's of course interesting to see other stacks but honestly it's not a crucial thing. My CTOs and I know what they are doing and of course we like to get inspired but yeah, at the end of the day tons of research, years of experience, debate and the individual use case decide our stack and not what some random website does. Same for design-relates stuff, btw to find a font-face is just a Command-Option-I away.
So no offense, but I am just wondering why you start a business which is already there, which is hard to scale and which is hard to get paid for.
Guess I missed something and happy to hear your view.