65% of American adults now use social networking sites, up from only 7% in 2005. Facebook is the most popular social network, with 71% of online adults using it. Other major social networks include Twitter, Instagram, Pinterest, and LinkedIn. Research shows that Facebook users are more politically engaged and trusting than non-users, and the platform helps revive dormant friendships. However, users are more likely to receive likes and friend requests than to initiate them themselves.