When friends incessantly comment on each other's posts even though they don't really know each other that well.
Man 1: I just went to the Chelsea Flower Show and wish I had a big garden!
Man 2: Why don't you move to Melbourne and you can :-)
Man 1: Funny, I was going to write that! xx
Man 2: Looking forward to seeing you in Madrid. Four more weeks! Woohoo.
Man 1: Can't wait! xx
Man 3: Boy, you two have a Facebook Crush going on...