Previous reports of Sony infection by Mac users were vague, and although the above article is a bit old, relative to what's been going on in the Windows world, it does give some clue...
It appears that the infected CDs carried a separate, but similar, DRM program for Macs. The disks contain a "Start.app" file that opens a EULA, stating that software will be installed; but without any description of what it is. "It actually installs two kernel extensions, PhoenixNub1.kext and PhoenixNub12.kext, in the OS X system files."
The Mac version comes from a different supplier, SunnComm, and no removal program or instructions have been provided by Sony. Apparently the installed files remain on the machine after you remove the CD. (To date, Sony has declined to discuss the Mac installation, so far as has been reported.)
There is discussion at the above page, in which several Mac users protest "but ours is different." While adverse effects on Mac operation are not well understood, the fact is that the Sony CDs install software on your machine without telling you what it's for or what it will do. Other reports, equally preliminary, have indicated that the installation can affect operation of Mac computers for other uses.
The software installed is described as limiting the number of copies you can make from the CD, and as "capable of making 'limited time' and/or 'limited number of plays' copies" that "expire" and become unplayable after a preset time/no of plays. But they don't tell you that.
The article linked above cites and provides a link to "additional info" but I couldn't find the information cited at the link, MacInTouch. I guess I just don't follow "MacSpeak" well enough. Mac users may be able to find the info (and/or interested enough to try), although it's also apparently a few days old.
Note that the information here, and in the article linked, is based on limited "user reports" and doesn't necessary come from known tech labs of the kind who've been reporting on the Windows version.
No indication whether this affects only OS X, or if that's just the version in use by the users who contributed to the report.
There have been reports of "something" installed on Linux machines, and of effects on machine operation, but they remain vague and unverified.