A thing I'd forgotten
I know I knew this because I wrote about it. But I'd since forgotten it completely. From Keith Olbermann, in a long-ago deleted post on MSNBC's website:
One further historical curiosity missed by The Record [perhaps defunct] and others researching the Red/Blue phenomenon. Before World War II, when there were only about five national radio networks, NBC owned not just one, but two of them. They were each identified as NBC, with the only differentiation being that the one originally owned by RCA was called the NBC Blue Network, and the one purchased by RCA from AT&T was called the NBC Red Network. The government later forced RCA to sell one of the networks (Blue) to the man behind Life Savers candy – he re-named it ABC in 1946.