Without the development of error correction codes and data compression codes most of the recent developments in communications technology (cell phones, high definition television, audio CD's, DVD's) would not be possible. Two big pioneers in this were Richard Hamming who developed one of the early practical error correcting codes (others were developed by Golay) and David Huffman whose pioneering work helped with the dramatic developments in data compression we see today.
Basic information about Hamming codes can be found here:
http://en.wikipedia.org/wiki/Hamming_code
Basic information about Huffman codes is also available on en.wiki.
