不错的基于socket编程的点对点CSharp开发的文件传输，不是FTP形式的。-good socket programming based on the point-to-point CSharp development of the document transmission, FTP is not the form.

IM即时会议聊天，可以点-点，可以点-群进行聊天-Real-time IM chat session, you can point- point to point- group chat