We are growing daily, and as we grow we find more things to keep track of. With Slack we've manage to create a simple integration to notify us on important matters of our software, for example, when a new user is created on any of our clients (automated billing process with Stripe).
When any of our servers are increasing the memory/cpu usage, also daily reports of all of our clients activities related to their website (Visits received, new leads generated, deals won/lost etc...)