The document discusses three social media platforms - Facebook, Vine, and YouTube. Facebook allows users to post statuses, photos, and videos and interact with others' posts. Vine focuses solely on short, 6-second looping videos that can be liked, shared and commented on. YouTube is a popular site to not only watch videos of all lengths, but also listen to music, find reviews, and learn new things through video content that can be engaged with through likes, shares, and comments.