sdr.hu is the home base for OpenWebRX, a remote spectrum monitoring system written by Andras HA7ILM.
The system is designed to allow OpenWebRX servers, running on RTL-SDR or HackRF hardware, to share their radio spectrum and allow remote tuning of the available radio bandwidth. A typical installation will allow up to four remote listeners to independently tune in, and the tuning filters allow the listener to independently control the bandwidth of the receiver.
A sample display shows WMVP-AM in Chicago monitored from SE Michigan.
Listening to the ALDS on ESPN 1000, WMVP-AM Chicago. Baseball (and radio DXing) instead of politics. pic.twitter.com/qFUMHDlqti— Edward Vielmetti (@vielmetti) October 10, 2016
The wide band version of this is the KiwiSDR, a BeagleBone based receiver which has been developed as a Kickstarter campaign. Look for those systems on the sdr.hu list with a receiver tunable between 0 and 30 Mhz. This covers all of the broadcast AM range plus shortwave broadcast and HF amateur bands.
sdr.hu is not the only system with links to web-tunable SDR receivers. websdr.org, hosted at U Twente in the Netherlands, has its own set of receiver software and hardware. Coverage is by no means universal, but between the two collections there are hours of DX listening ahead of you (including, for my purposes, lots of alternatives to pull in baseball playoff broadcasts).