- apache
- lighttpd
- v8
- PostgreSQL
- Linux
- Go
- ZeroMQ
- any imaging library (libpng, libjpeg)
- any compression library (zlib, xz, bzip2)
- urxvt
- vim
- emacs
- tmux
Basically none of these have good websites. When I'm looking for a CSS framework or like, UI tricks like scriptaculous then I think it's a good signal, but past that I really think there's no link here. Really "has a good website" means "someone who knows how to build good websites built one for this project".
Sure because those are examples of what you can do with the tech. You can't really make a website with Qt, so using... PyQt's website as an example for evaluation doesn't make a ton of sense.