This is exactly how we've handled Slack. It's sync (to within a minute or two) for @ messages, which are used sparingly. It's async for everything else, and i

This is exactly how we've handled Slack. It's sync (to within a minute or two) for @ messages, which are used sparingly. It's async for everything else, and it's faster than email only in that it's a bit more conversational. Within that norm, all of the "Slack is an evil attention vampire" complaints feel deeply unfamiliar to me. I find it less distracting than email because @ makes message priority clear at a glance.