This document discusses socket programming in .NET, including how it can be used to create a chat application. Socket programming allows communication between applications through TCP/IP and uses the System.Net.Sockets namespace. A chat application would require a server that can connect to multiple clients simultaneously and asynchronously send and receive data from each client. The clients must also be able to asynchronously send and receive data from the server to allow for real-time chatting between multiple connected users. Security considerations are also important for such a networked application.