Snapchat is a photo and video sharing app popular among young people that allows users to send photos, videos, and messages to friends. Photos and videos, known as "snaps," sent through the app are only viewable for a short period of time before disappearing. The app also allows users to post snaps publicly to their "Story" where they remain viewable for 24 hours. Key features include filters, lenses, stickers, and chat functionality for direct messaging between friends.