I'm gearing up for a 2018 "no social media on weekends" and I tested it this weekend. When I logged in to FB this AM, I had 10 notifications:
Most were:
Britt added a new photo.
You have a new friend suggestion: Gloria.
Tiffany updated her status.
Jeff updated his status.
June updated his status.
Lily updated her status.
These are people that I assume the algorithm thought would "suck me back in". It was really fascinating to see how the algo was stuffing my notifications to fuel that dopamine release.