We're building an app in AngularJS right now and have had to think about this. What we concluded was for our use case, if they weren't happy running JavaScript

We're building an app in AngularJS right now and have had to think about this. What we concluded was for our use case, if they weren't happy running JavaScript, they probably weren't going to be happy with our content which is live video streams. We also took a long hard look at browser compatibility and decided we didn't care about anything below IE9. That's a ballsy move to some people, but we are a modern tech firm developing modern tech. We're happy to build the best experience we can using the best technology, and letting the market come to us. If they can't access it because of technology reasons, well, somebody else can pick them up as an audience. If they can't get a modern browser running on their Windows 95 box, they're probably going to be happier installing Linux and something a bit more modern anyway. The one area where there is some pushback is accessibility. I'm not just talking about screen readers here, but colour blindness and navigational coherence. You don't get to choose what technology and capabilities your audience have, but you do get to choose if you care about them. In our case, we have decided the cost of supporting the 2%-5% we're actively excluding would actively harm the rest of the audience in a noticeable way - so we have chosen not to do it.