This document discusses 4 major social media platforms - Facebook, Instagram, Snapchat, and Twitter. Facebook allows users to post statuses and photos for friends, and easily upload and comment on photos. Instagram focuses only on photos and videos, with commenting and filter options. Snapchat sends photos and videos that disappear after 10 seconds or less, or can be added to 24-hour Stories. Twitter allows posting of statuses, photos, and videos, but replies must be new posts tagging the original person.