Here's my test of whether a message should be sent via email: "Can I reply to it?" If the answer is no then it probably shouldn't be in email. Think about all of the do-not-reply@ messages that come in that are notifying you of something happening in some other system. email is for communication but too often is just used for broadcasting one way messages. If I had an easy way of filtering out these messages I could easily reduce my inbox by 90% - down to things sent by humans that I need to respond to. Everything else could go into some notification feed, the problem is that there's no standard protocol for that so everything ends up in your inbox.