Looks like no one's figured out the new app yet. The name of is it Squeeze and it's currently in beta. I happened across it yesterday.
HFS, the filesystem used by MacOSX, has an ability to read and write in a "compressed" form. Those with the knowledge on windows can see it as the Mac's NTFS-compression. Squeeze is a background file compressor for this ability.
Basically with squeeze you have a real-time extraction when you open a file or application. In exchange for a small addition of time (which isn't so big now that I've tried it), your files will take less space.
It does take a while though. At least the first time it compresses things. Oh, and to those wondering, it's a prefpane.
I'll post more details as I am able.
䷟䷽䷏䷁ — Dying of the Light.