1. Facebook, like any other online platform, has terms of use. Respect them or be prepared to be banned as well as criticized mercilessly.
2. Facebook is about relationships. You don't have a "relationship" with a door-to-door vacuum cleaner salesman - so don't be one on Facebook.
3. Being personal is everything. Successful Facebook marketing campaigns revolve around personality.
4. There isn't a magic formula for making any message "go viral." You can't control a virus - that's what makes them viral.
5. People like Facebook for entertaining stuff. In fact, entertainment is defined as "holding one's attention." Remember this.
6. Facebook ads are more personally targeted than ads anywhere else.
7. Being "liked" can work very, very well for your message. Being "unliked" (no, there's not a button, but it can happen) can bury you.
8. Facebook is in control. Always remember this and don't ever, ever assume its available tools won't change. They have and they will.
9. Don't build a business on Facebook marketing - or Twitter marketing - or newspaper ads, radio ads, TV ads, or leaflets dropped from hot air balloons. Build your business on a great product, a great message, and great relationships.