> Many startups (e.g. Slack) aim to replace email Whether or not this is an 'aim', chat (slack, texts) is a distinctly different medium than email, in the same

> Many startups (e.g. Slack) aim to replace email Whether or not this is an 'aim', chat (slack, texts) is a distinctly different medium than email, in the same way voice chat is. Voice is synchronous, real-time communication. It's very immediate, but demands 100% attention while taking place. Email is asynchronous, with an inherent delay from the slow workflow and turn-around time. It takes at least a few distinct actions to read and send a reply, and there's no indication if the person received your message or is replying (unless you're a sociopath that uses read receipts, anyway). You can of course reply quickly back and forth and get close to a synchronous medium, but it's at best awkward and just really doesn't work well for this. Chat lives in the middle ground where it is kind of both: though it's really async, most platforms have an indicator of online/offline, typing, etc, and the friction to reply is very small, so it works well synchronous. More importantly, in my mind, is the expectations that come with the medium. Chat is casual, ephemeral, and has no expectation of response. After some minutes/hours/days (depending on context) a message goes stale and that's just how it is. It's also perfectly fine to reply "sorry, in a meeting until 2" or "not sure, maybe ask @otherperson?". Email is more formal, long-lived has an expectation of a useful response. This turns your inbox into a todo list where all the items are added by other people as they see fit. The types of deferrals you can do in chat don't really work in email. There's definitely disagreement on these, and that can cause a lot of friction between people that treat them differently (for example: people that use email as if it's chat drive me absolutely crazy -- let's just chat and finish this conversation in 1/2 the time, or have a voice call and finish it 1/10th the time!).