RealNetworks is one of the big pioneers of streaming media and Internet multimedia, starting from around year 1995.
Their first project was RealAudio which was the first really popular program for streaming audio. After that, there was a huge growth in the number of "Internet radio stations". (in Finland, this stirred up some discussion among the so-called "IT experts" of big monthly magazines - think of it, radio stations without need for permits!) the sound quality of the program was pretty good, even with 28.8k modems.
Later, the program grew to streaming video side, too. RealPlayer just started to show video at some point. Then, for some reason, RealNetworks heads suddently realized they were Kings of the Internet and let their illusions of grandeur a little bit too loose. Gradually, RealPlayer, from interface side at least, started to suck.
Moreover, these days RealNetworks has become more like an enemy than a friend. They have engaged in spamming. The current versions of RealPlayer deceivingly try to trick people to mailing lists and such.
Ahem. I digress.
Aside from RealPlayer, they also make the counterpart in server side (RealMedia server), and also make more media players and media tools than I have fingers and toes for.
The corporate home page is at http://www.realnetworks.com/.