humanzip is a compression program that operates on text files.  Unlike
most compression algorithms, its output is human readable.  Indeed, it
is explictly meant to be read by humans and might even be easier to read
than the original.

humanzip compresses files by looking for common strings of words and
replacing them with single symbols. The idea is to reduce the screen and
print size of documents.  Humanzip does not explictly try to reduce the
size of the file as measured in bytes, although this usually happens
incidentally.

WWW: http://savannah.nongnu.org/projects/humanzip/