> There's way too much noise in my email inbox, stuff gets lost.
I find that happens an order of magnitude more often in Slack than email. The number of times important things here don't get done on time (or at all) because "Oh, I must have missed that in Slack...)
Important/immediate discussions take place in person, or on slack. (Or hipchat or sametime or lync or windows messenger or hoary old ICQ for all I care...)