It's running Discourse forums, a YC-funded thing, also OSS, authored with Ruby on Rails. I find it fascinating that people are praising their skin of Discourse

It's running Discourse forums, a YC-funded thing, also OSS, authored with Ruby on Rails. I find it fascinating that people are praising their skin of Discourse, because I think it's got a little too much white space! With those needlessly huge button-banners, for folks with small-to-medium sized screens, the content of interest is almost a full screenful-scroll away.