YO! is described as ''s lightning-fast HyperNet technology let you connect anywhere - without using expensive data plans or internet. Share and discover new apps, photos, videos, music, and files offline with friends and family nearby' and is a Social Network in the Social & Communications category. There are six alternatives to YO! for Online / Web-based, Android, iPhone, Facebook and Facebook Messenger. The best alternative is Briar, which is both free and Open Source. Other great apps like YO! are Facechat (Free), NickEgo (Free), Bridgefy (Free) and WorldChat (Free).
An open-source decentralized and encrypted messaging app even without internet connection via Wi-Fi and Bluetooth. Messages are stored securely on your device, not in the cloud. Connect directly with nearby contacts - no Internet access is required.