I'm going old school, promoting RSS and offering an email address + call-in number with vmail and no comments on the page. I post video to CDN, do live streams with ~5sec latency (could be reduced I think). I post editorial style, sometimes have live chat for live streams via twitch. To self host I could just use an xmpp server with strophejs on the page, live streams might get a few thousand concurrent. Delivery works via HLS + CDN so scalability is in theory not an issue, although I've not tested multi-region viewership yet.