Using your facebook updates to try and show other people how great your life is so that they will envy you.
Guy 1: *on facebook* Wow! Great day surfing in San Diego! @Alex Dennis: "How many dollars in a sombrero!" Hahahaha lmao good times!
Guy 2: Why does he need to post that on facebook?
Guy 3: He wants people to click like and validate his post, indicating a symbolic acceptance that his life is better than theirs. It's a classic case of smugbooking.