Please refer to Facebook Specifications (Promotional Guidelines at:https://www.facebook.com/page_guidelines.php#promotionsguidelines).
The most frequently violated principles:
- All promotions must be managed by a third-party application.
- You may not use Facebook features (likes, comments, videos, photos, cover photos, etc.) as a registration or participation mechanism for promotions.
Facebook features, such as the "Like" button, cannot be used as a voting mechanism fo.r promotions