In my personal experience, the biggest wedge is in planning events. With the caveat that this probably only applies strongly to people currently in their mid-twenties:<p>For a lot of social circles, facebook is the only service that almost everyone will regularly check and that lets you coordinate events. My friends who don&#x27;t use facebook will regularly miss (or not get invited to) parties, book club, skiing trips, etc. This isn&#x27;t because no one likes them or thinks to invite them, it&#x27;s because they opted out of the platform.<p>The other big point of stickiness that I can think of is that facebook is many people&#x27;s cloud. Years of photos are backed up there and only there. It&#x27;s unfortunate that they&#x27;ve relinquished control of their files to a closed-platform third party, but that&#x27;s the way it is.