I don't want to harp on this, but this is a great example, I got in a Slashdot submissions bin, of confusion over the name of the OS.
Microsoft has released a remote desktop app to allow users of OS X to connect to Windows Servers running terminal services. This is rather a nice little app and runs natively in X. I had been using RDEsktop running under OroborOSX, but this runs nativley and has a rather small footprint.
He mentions both Mac OS X ("OS X") and X11 (via OroborOSX, a frontend to XFree86 for Mac OS X). From the context you can guess he intends "X" to refer specifically to Mac OS X, but noticing he was talking about X11, I at first assumed he meant X11. Maybe "OS X" is specific enough, though I think it's lame shorthand (like "'nix"), but "X" is not acceptable at all.