We all now that email, being a technology created a long time ago and developed organically into some sort of lingua franca of Internet persona and communications, has a series of problems. No easy ones. Manage the email is a problem of its own, and there are lots of articles about it on the Internet.
One of the most annoying is the notifications. We all receive too much email that are only reminders of something relatively interesting in a different app. That could be a new comment on a blog post, an update on LinkedIn, or even a new post on a forum (yep, that used to be a huge thing). GMail’s recent move to group together all notification email is a great example that this system is quite inefficient. It is difficult to find the balance between keep a user informed and not sending spam.
To increase the annoyance, notifications typically will be produced in bursts. There is some discussion in a blog, with 4 or 5 messages in an hour, then it stops for several hours, and then someone else post another comment, producing another couple of comments.
My impression is that any serious app that produces a significant number of notifications (not even very high, something like twice a week or more) and wants to show some respect to their uses should move to a notification system. Hey, Facebook has done it. Remember when Facebook used to send tons of mail everyday with new likes, friends and posts? They changed that to make a notification system in their page. That mean you can always close Facebook, and when coming back, you can easily go to everything since last time.
But, of course, Facebook is a special case, because most people keeps it open or at least check it regularly. Most of other apps that are not that frequently used needs to use email, or no one will check them.
So that’s the deal. Send only one email. One saying “You have new stuff on app X. go to this link to check your new notifications. No new email will be sent until you visit our page” And maybe send another reminder after a week (that can be disabled). This way, if I don’t want to go immediately to the page, no more spamy notifications are received. If I’m interested in the app, I’ll check every time I get that email, but the email is not spam. It allows a very interesting natural flow. And it also shows up respect for your users.
PD: Yes, I know that this is inspired by the way phpBB works, but in a more high level approach. Not sure why that way of doing stuff is not more common.