The early wireless communication technology invented and pushed by Guglielmo Marconi was based on electrical sparks creating bursts of radio waves. This was fine for transmitting Morse codes, but the signals used a very broad spectral range - it was not possible to tune in to a specific station as we are used to today - and could not be modulated to carry music or voice. The German word Rundfunk for radio broadcasting goes back to this technology: Funken is the German word for spark.
The Canadian engineer Reginald Fessenden had the idea to use a continuous radio wave of a specific frequency as a carrier to transmit a signal. He constructed a high-frequency alternator that produced frequencies up to about 100 kHz, and experimented with this technology in 1905/06. His original idea was to build a wireless telephony system, to offer some alternative to the monopoly of the dominating telephone companies. He had to cope with some problems and drawbacks, but then, to cite from this paper:
Fessenden's greatest success took place on Christmas Eve 1906, when he and his colleagues presented the world's first wireless broadcast. The transmission included a speech by Fessenden and selected music for Christmas. Fessenden played Händel's Largo on the violin. That first broadcast, from his transmitter at Brant Rock, MA was heard by radio operators on board US Navy and United Fruit Company ships equipped with Fessenden's wireless receivers at various distances over the South and North Atlantic, and in the West Indies.
Fessenden and Marconi: Their Differing Technologies and Transatlantic Experiments During the First Decade of this Century, by John S. Belrose; International Conference on 100 Years of Radio, September 1995.
100 years is a long time ago, and for me today, used to sit comfortably on a sofa with my notebook and connected to the internet via WLAN, its is hard to imagine the world before radio broadcasting. But then, I remember my grandparents, my father's parents, who were just kids in 1906. They grew up in a world very different from today, to see so many things happen and change. What will be in 100 years from now?
Merry Christmas to all of you!