You wouldn't guess it, but Facebook owes a lot to lowly email, the most basic and ancient form of communication on the internet. Users receive email notifications about almost anything that happens on the site, dragging them back to Facebook to reply to messages or check out new events.
Without the benefit of an omnipresent toolbar with notifications, aka the Google navbar for Google+, email is the next best thing for Facebook.
But, the most active users, who would be the most engaged, may be the ones benefiting the least from email notifications.
Those constantly bombarded with friend requests or new messages turn off email notifications altogether to let them get on with their work.
Now, there's an alternative to turning them off completely. Facebook is experimenting with summary emails, which come in less frequently, once a day for example, and contain all of the notifications and requests from that day.
This way, users get just one email rather than tens. This feature will be enabled by default for the most active users, who receive a lot of email messages from Facebook each day.
"We're testing a feature for people who are very active on Facebook and receive lots of email notifications from us. We'll provide a new summary email and turn off most individual email notifications. If you want to turn them back on, there's a control in your account settings," Facebook wrote on its Wall.
Note that the feature will be enabled by default only for the most active users, those getting only a few email messages per day will continue to receive them.
It's interesting that Facebook is pushing the change and making it the default. Those that actually want a lot of emails have to disable the option. But if these users weren't bothered enough to disable email notifications so far, it must mean that they can handle tens or hundreds of emails per day. Disabling them altogether is sure to cause a backlash at least with some users.