Yik Yak is an anonymous social media app created in 2013 by two college students to allow local users within a 5 mile radius to post messages ("yaks"). Users can read, reply to, and vote on yaks without revealing their identity. The app encourages positive engagement within the local community by allowing users to connect anonymously. It has features like viewing top yaks, users' recent posts and replies. Users are expected to follow ground rules against bullying or posting personal information to maintain a respectful environment for sharing thoughts locally.