I am largely the same person online as off, although I am much more outgoing online. In person I am really shy and I find it very difficult to meet people and make friends. I can't even remember the last person I met and became friends with in person -- it has to have been at least a decade ago. Online offers me the ability to think through what I want to say and better plan how I present myself. I can also back out of uncomfortable situations online much easier (the old "Sorry! My computer locked up" line comes in very handy) online, so I'm much more willing to jump into conversations than I would be in person.
For the past 15 years I have been a full time caregiver to my disabled aunt and, until her death several years ago, also to my mom...not having an outside job, and having the time I can spend away limited also cuts down on the meeting new people opportunities. So for me, online communities, including social media sites, have enabled me to have contact with people and to make friends.
And I'll admit it -- I am one of those people who has posted about what I had for breakfast (complete with photos of the waffles every stage of the way from batter to plate). But we did have a highly intellectual discussion of the merits of various waffle toppings and methods of consuming them, so it should be acceptable to the FYM crowd.