It sounds like she was on facebook all day long. I know people who are on it 24hours a day almost. I know FB sends a notice when someone comments on a thread you post on, so that was probably part of it. She sounds very toxic. Some people are unhappy and want to make others unhappy too, or attempt to destroy them mentally in some way. I had a friend who was hyper critical of me, this was IRL. Then one day, we started trading emails occasionally; well, she loved email because it made it easier for her to send me vicious messages. Things she wouldn't have said IRL. It was like it was easier to throw out insults when she was sitting behind a computer screen. Life is too short to put up with people like this and I started making new friends ASAP. I realized she'd never change.

I have at least one FB friend that I've excluded from seeing most of my posts, because she would comment on every single one. She also friended people from my friend list, and started bugging them, too. She has over 5,000 "likes" of various businesses on FB. She'd have to be on FB all day long to have this much activity going on. Some people live through Facebook. I decided to only post on it occasionally and limit my friend list to just family and people I went to school with. I don't spend all day looking for people to send friend requests to, or post one anyone's page and I avoid all the political arguments and drama.