This project exists as an alternative to paid services that show you what technologies are running on a given website.
The impetus was another project of mine, Adaptive Testing Methodology, which gives a customized set of testing steps based on what site you're testing and how much time you have.
But in order to do that, you have to know the technology stack for a given site. I started by trying to use existing services, but quickly got hit by either call limits or significant costs.
So I have created this as a free alternative.
One thing that's different about this approach is that I'm looking for certain things and telling you if you have them (with a focus on the big blocks that make up a site and could affect its security).
The point is that I am not listing every possible thing on the site. I'm not mentioning that there is JavaScript, or HTML, or fonts, or whitespace. I don't find knowing those things to be terribly useful.