Sudden Mutual Liking (of everything).
Two people suddenly start liking everything, the other person posts while not showing publicly that they are close (they don’t post on each other’s walls or tag each other). It means that there is a certain tension and excitement between the two. Liking is equivalent to paying attention to someone or giving someone a compliment/support in the offline life. It is a sign of interest in someone as a friend, colleague or as a potential partner. Sudden mutual liking usually means that two people are sharing a private inbox, possibly a bed even.
Usually this initial excitement about the other person disappears as suddenly as it appeared, or it grows into a proper public relationship.
“Have you notices that Elena and Maggy SML a lot lately? I don’t think they even know each other offline.”
“We never communicated. For now we are in SML stage, but it encourages me to write him a message.”