Facebook has banned the “Secret Crush” application due to its affiliation with a notorious spyware manufacturer.

The social-networking site confirmed the breakup on Monday: “Facebook is committed to user safety and security and, to that end, its Terms of Service for developers explicitly state that applications should not use adware and spyware,” a statement from the company read. “We have contacted the developers and have disabled the Secret Crush application for violating Facebook Platform Terms of Service.”

The move comes a day after Sunnyvale, California-based security firm Fortinet took the social network to task for allowing the malicious application to propagate across the site.

Applications that promise free things for nothing (such as ringtones) should always be suspect, so caveat emptor. Facebook and MySpace will become fertile ground for more companies to attempt to turn a profit from their popularity through dubious methods. These companies will have to step up and closely police the widgets and pages that are part of their universes.