Confluence and Linchpin have an effective way when it comes to notifications. I admit that some people out there think the standard notification system is broken as it sends too many mails in their opinion.
Confluence has a very smart way to pull your employees into the conversation. Whenever someone interacts with a page or an element (e.g. liking, commenting, editing, enhancing, watching) the software will activate the auto-watch-feature for that user and that element. Future changes will be batched in a definable interval and send to the user via email or in-app-notification. This way natural conversations evolve and everyone is free to opt-out of the notifications whenever they want.
One approach to the Confluence mails is to configured the system differently which can be done within minutes (turn off auto-watch, …). You can even run Confluence without an email server.
Actually most of our customers learn, that Confluence has a productive. Way of sending notifications that fosters their collaboration internally. That’s where you can understand best, why email is the problem at one hand, but is part of the solution as well.