The document summarizes several social networks including Facebook, Twitter, and Tuenti. Facebook was created in 2004 by Mark Zuckerberg and is used to connect with friends and see new information. Twitter was founded in 2006 and allows users to follow celebrities and have conversations. Tuenti is a Spanish version of Facebook that was created in 2006 by friends in Spain. The document discusses how social networks can be used to learn about hobbies, music, and more but also notes there are negative aspects like wasting time and not knowing other users' true identities.