Looking at the newsfeed on Facebook and coming accross a status update where the writer is welcoming likes or comments but no-one does. Therefore 'liking' the status, not because you actually like it but more that you sympathise with its creator.
Penelope: "Dude, did you see Karen's last status update on Facebook...?"
Patty: "Yeah it was not funny at all, what was she thinking?"
Penelope "I have no idea, I felt so bad for her though so I pity liked"