WiFi SON (short for Self Optimizing Network or Self Organizing Network) is a software feature of WiFi routers that constantly examines network conditions and re-configures the WiFi router to perform better.
WiFi SON focuses mainly on selecting the best frequency band and specific frequency channel to use, depending on client capabilities, signal conditions and interference. As conditions change from minute to minute and second to second - WiFi SON is important to keep the home network performing at its top level all the time.
In addition, WiFi SON can implement various other functions. For example, with WiFi Mesh Network Systems WiFi SON can select the best internal route (from the client through mesh routers to the primary router) to achieve highest throughput and lowest latency.