After you've viewed Jim Hamm's alert (just below) go to this other article at How To Geek (Mac OS X isn’t safe anymore. The crapware/malware epidemic has begun). See illustrated examples of screens that are “like the Old Faithful of bundled crapware.” Examples show Yahoo, CNET downloads, OpenOffice, fake Java messages, MacKeeper, etc. It discusses the plist file, and says to restrict Apps that aren’t from the App store.