chat

Chat is a form of communication that enables real-time or near real-time exchange of text messages between two or more participants over a network. It is commonly delivered through dedicated applications, web services, or integrated features in broader platforms, and may include attachments, links, and multimedia.

Historically, online chat emerged in the 1970s and 1980s with early bulletin board systems and multi-user dungeons, followed by specialized networks such as Internet Relay Chat (IRC) in 1988. The 1990s and 2000s saw a rise of instant messaging clients (AIM, ICQ, MSN Messenger), which popularized personal and business chat. More recently, mobile and web-based chat apps have integrated features like file sharing, voice and video calls, and bot automations.

Chat services use client–server architectures or peer-to-peer elements and commonly support synchronous (live) conversations and asynchronous features such as message history and presence information. Common concepts include channels or rooms, direct messages, message history, typing indicators, and read receipts. Widely used protocols include IRC and XMPP; modern platforms include proprietary ecosystems and standards like WebSocket-based messaging, and sometimes end-to-end encryption.

Security and privacy considerations include authentication, encryption, data retention policies, and moderation. Users should be aware of potential risks such as phishing, spam, and harassment. Etiquette and guidelines vary by community and platform but generally emphasize respectful communication, consent for sharing content, and adherence to rules.