3. FacebookHBO is using all things social media -- Twitter, Google's ( GOOG) YouTube and, of course, Facebook ( FB) to get the word out in the digital realm that Winter Is Coming ... this Sunday. The official HBO "Game of Thrones" Facebook page has more than 5 million "likes." HBO's latest post, as of Thursday afternoon, promoting its traveling exhibit of the show got a whopping 20,000 likes. It's examples like "Game of Thrones" that really allow Facebook to live up to its true potential of being a platform for people with similar interests to share and engage with one another. The "Game of Thrones" case study also plays into Facebook's January announcement regarding Graph Search, in which users will be able to combine phrases to search people, places, photos and other content that's been shared on the social network. Facebook shares have been on a rocky road and are down 4% in 2013. Shares closed at $25.58 on Thursday, down 2% for the day. -- Written by Laurie Kulikowski in New York. Chris Ciaccia contributed to this article.Follow @LKulikowski To contact Laurie Kulikowski, send an email to: Laurie.Kulikowski@thestreet.com. >To submit a news tip, email: firstname.lastname@example.org.