When many people write on the wall of a recently deceased person. Their posts usually consist of fond memories them and said person shared, their last moments with said person, describing how great said person was and what a shame it is for them to have passed on and for those who have little to say, well, they show their remorse with a <3 Its basically like a funeral service, internet style.
EXAPLE OF FACEBOOK FUNERAL POSTS
Mia : "Hal, i miss you so much. It's so unfair that this happened to you. I hope to see you again someday..."
Gill: "You were a good guy, I'll miss you buddy"