Only works with certain files with repetitive binary info as in text files. Mostly, kgbarchiver is a hoax but it does achieve a higger compression ratio than other archivers like winrar.
However it has low efficiency, i.e. needs exhorbitant amounts of ram and cpu which average computers don't have (perhaps if you own a supercomputer).
Even UHARC can achieve some good compression (i once compressed a 124mb file folder to 8mb. Took 2 days. Does not always work. Waste of time. I still have the file.)
There is this dream of the infinite compression algorithm with a rotating dictionary
Someday it might be possible. But not today.
My advice, wait for the big boys to make something better. Till then use 7zip for compression and Uniextract for extraction.