Are There Any Legit "Rules" for Submitting DYKs?

[Pogue-Mahone]

When we submit Did You Knows to the site:

1. Is it preferred that they come from our own experiences with the games?
2. Is it acceptable to reference trivia from other sites so long as we credit the person that originally found the trivia?
3. For excellent Did You Knows that should be on this site, but are not (I've seen a good few that deserve to be here), should we suggest to that person to submit their findings on this site, or just submit that trivia with a reference?

Are there any other guidelines we should follow on the site?