Some organizations use social media as their primary (if not their only) means of communicating with members. My gym, for example, uses Facebook to post day-to-day announcements.
That doesn't mean it's not possible to opt-out. It just means you need to give up something to do it. I'm not on Social Media (unless you consider HN to be), so it is possible.
the_snooze|7 months ago
ryandrake|7 months ago
Joel_Mckay|7 months ago
See Privacy Badger for details... =3