I have some people from JM and another site I visit, but they are all people who I communicate with pretty regularly.
I have some not close family members on it so they can see pics I post. We live very far from all our family. I have a few HS friends- a couple who I was never close to, but knew, and a couple who were my best friends but we lost contact after HS.
I would not add a random person who I met at a party though, unless we formed an actual friendship.
Oh and I put I would add a teacher. I might, but it made me laugh since I recently friended an old student of mine
I taught her in 7th grade and she is now a senior in HS!