Although I think that might be interesting, would it actually be valuable? Serious question honestly, what would that do for us? How would we use that data?

I guess it depends very much on the company. If the company is doing something cutting edge in the web app space then it might be interesting. If, on the other hand, they're a robotics or biotech company then who cares if their home page is just a hosted WordPress site.

Probably highlight some interesting bits and pieces in relation to the whole "use boring tech" vs "use bleeding edge tech" argument that so many people seem to make.

It would certainly increase the awareness of it.

To discuss it? I guess?

https://stackshare.io/stacks gathers data about which frameworks are used by tech companies - though probably none of the startups from the article are listed here yet.