What is the difference between background and Fluff?
Background is the setting that a story, tale, or intellectual property is based in and around. Everyone who was paying attention in grade school learned what a setting was. 40K is based around the Imperium of Man, led by the Emperor and the 12 High Lords of Terra, the Imperial Administratum, and the Imperial Militant arms (Sisters, Guard, Marines, Battlefleets, etc), invading and marauding aliens, and all the stories regarding our favorite characters, armies, vehicles, and so forth. This is background.
Fluff is a most delicious marshmallow treat produced by Durkee-Mower, Inc in Lynn, MA. Its ingredients are simple - corn syrup, sugar, dried egg white, and vanillin. I'm not sure what vanillin is but I think Vanillin Villians might be the ones using fluff incorrectly. You can purchase Fluff in most good grocery stores and it tastes delicious.
Fluff
Fluff can be used to make Fluffernutter sandwiches which are simply a Fluff and Peanut Butter sandwich. They are fantastic sandwiches and if you haven't tried one I recommend that you do so immediately.
My daughter likes Fluffernutter sandwiches. Kids love it!
No where do I see Fluff in my rulebook or army books. Know thy enemy. Learn to spot the differences.
Here is some Fluff on my rulebook.
Can you spot the Fluff and the background?
Fluff under the rulebook. Background and setting still in the book.
This isn't Fluff either, just snow from yesterday's 2nd big storm of the winter season. But if it was Fluff, it would be free and tasty but hard to shovel!
Don't abuse Fluff. Please use Fluff responsibly. Friends don't let friends use Fluff inappropriately. Put it on sandwiches, ice cream, brownies, and other delicious desserts. Feed it to your kids, friends, wives, husbands, in-laws, aunts, ants, and small woodland animals.
Don't use Fluff to describe background or setting. Know the difference and show your intelligence.