How much time to do you spend in the shower? Wait...don't answer that.
It was my understanding that you have to listen on a terrestrial basis to register in the PPM. Did Nielsen change this to accomodate internet-based listeners?
The radio ratings include streaming of terrestrial stations. If the stream is a 100% simulcast of the over-the-air broadcast, streaming and OTA numbers can be combined in a single figure at the election of the station.
Streaming is always registered in the diary method... it just depends on the listener remembering to write it down. The diary also picks up satellite listening and even pirate stations... whatever the listeners thinks is "radio" (and most listeners think Pandora is "radio", too).
The PPM picks up encoded signals from terrestrial stations including streams and HD signals. Each audio "source" is separately encoded, but simulcasts are usually combined.