In the "Good Old Days", a SWL would send a QSL, or reception report letter, and as mentioned, usually to a commercial station, either in the U.S. or abroad. I sent several of them when I was young, and got many replies. I don't know which excited me most, the response from a Foreign Broadcast Station, or a Ham stateside... Later when I became a Ham, I remembered the responses I got, and in turn, I responded to ALL SWL reports. I don't operate much HF now, but if there was a report sent, I would by all means reply to the person. I am afraid that in this day and age, it may not be considered by many as something they should do, as many do not return a QSL, unless it is for some hard to obtain station in a contest. Had I not been so well received, I might not have continued on with my radio hobbies.
Knightrider...