VHF Propagation measured by APRS

Reading up on 2-meter or VHF propagation, I recently stumbled across a website that displays APRS propagation, overlayed on a map of the USA. APRS is a digital broadcast over VHF 144.39 MHz, and is picked up by digipeaters and Internet gateways for telemetry reporting. Most people familiar with APRS look up stations on aprs.fi, however, this new website shows how far from a source a signal is being received. I added this to my Radio Wave Propagation page, where I explain how radio waves reach their destination, and list other websites that show HF propagation.