"Newsfeed, not stalking."
To be put at the end of a comment on someone's Facebook post as a reassurance to the recipient that you are not stalking them, their post merely came up on your newsfeed and you felt the need to comment on it.
Person A writes to Person B: "Want to go to the cinema tonight?"
You comment: "Can I come? (NF,NS)" at the bottom of the post to show that you're interested in joining them, but not that much of a social loser that you're stalking either of them.