A look back at radio "SOS" messages

[Richard Chonak]

BBC Radio 4 has a 30-minute program about a piece of radio history: how 
BBC used to have a nationwide "SOS Message Service" starting in 1923 
that helped police make last-resort appeals to the public. It was used 
to inform travelers of their relatives at home who were in danger of 
dying, to seek witnesses of car accidents, and even to locate missing 
persons.

The program tells stories of how the service affected people in very 
personal ways.

http://www.bbc.co.uk/programmes/b01mdf9r

The program is available on-line until Sep 10.

I suppose a modern analogue is in message services like the "Amber 
Alert".  Are there others?

--RC