I was baffled by the references to following and muting until I realized that I probably won't see any of that since I have most of my subscriptions set to NoEmail and the other 2 are set to All Email.
"Following" is still useful for those read by web - there's the "Followed Threads" tab of the Inbox page which can give you a concise list of the things you're interested in (rather than having to plow through the entire Inbox). "Muting", not so much.