Yik Yak

Yik Yak is a microblogging app that allows people to post messages (yaks) without user names; the mobile app aggregates and presents the posts of users within a 1.5 mile radius as a streaming data feed.

Users can reply to messages anonymously and vote posts and replies up or down. The app combines instant messaging and GPS technologies to enable posting within the specified geographical area. Geofencing be used to block Yik Yak within specified areas.

Yik Yak features include:

• Yakarma: A numerical score based on upvotes and downvotes received and given.
• Upvote/Downvote: User votes to raise or lower the score of a yak. The higher the score, the more it affects Yakarma. Yaks that reach a score of -5, on the other hand, are automatically deleted.
• Peek: Enables view-only access to Yik Yak community feeds from other areas, such as college or university feeds.
• New/Hot Tabs: The option to switch between a chronological feed and a feed of the most popular yaks, based on upvotes.
• Other Top Yaks: The current Google image result page from searches for the word "yak". Typically all images of the animal.
• My Herd: Allows users to designate an area such as their home, workplace or campus as their base camp and post to it even when they are not in range.
• Photos: Allows users to include images in yaks. Photos are moderated for unacceptable content and displayed in grids of locally-posted images.

After Yik Yak launched in 2013, it was criticized for providing an anonymous channel for cyberbullying. Multiple high-profile incidents led the developers to block the app near high schools and middle schools the following year.

Although Yik Yak enables anonymous posting, that doesn't mean that messages can't be traced back to their sources. Users are required to provide a phone number for sign up and Yik Yak stipulates that they can provide police with user IP addresses, GPS coordinates, device details and data and time for each message if supported by a search warrant, court order or subpoena. As a result, Yik Yak users have been arrested for making threats of violence in their posts.

According to some security and privacy experts, what Yik Yak offers is really pseudoanonymity -- the appearance of anonymity, but not the reality.