Real-Time Messaging Protocol (RTMP) is a versatile protocol developed by Macromedia for streaming audio, video, and data over the internet, primarily between Adobe Flash Player and servers. It supports live and on-demand media with low latency but is vulnerable to bandwidth issues and requires Adobe Flash Media Server for transmission. Alternatives like HLS, HDS, and MPEG-DASH exist, but RTMP remains essential for Flash-based streaming.