Facebook touts over 500 million users worldwide. Assuming you're an average user and have kept the default notification settings or something close to them, then an e-mail is generated every single time that anyone:
- Sends you a friend invitation.
- Writes on your wall.
- Posts a status update in a private group to which you are subscribed.
- Comments on a status update you made or on a photo you posted.
- Comments on a friend's status update or photo after you have left a comment.
Given the above and the claim that the average Facebook user generates 90 pieces of content each month, that's a whole lot of notification. Enough to make me wonder about how many e-mails and how much data center capacity/energy would be saved if everyone, say, just turned off those notifications and found out about all that stuff the next time they actually visited their FB page.
I'm guessing it's enough energy to notice, but I'd love to get some input from some people in the know. Or even semi-know. I'll try to flesh this out some more for print, but I thought I'd throw it out there for now. Got anything to add?