[WillyF]

Even "real" truffle oil (or butter or some other fat) need not contain real truffles. It's quite easy to infuse fats with truffle aroma. If you put truffles and a fat (with sufficient surface area in contact with the air) in an enclosed place like under a bowl in a refrigerator, you will get a very significant truffle aroma/flavor in the fat.

I've done this with Oregon white truffles (tuber oregonense) that I harvested with the help of my dog. Kept the butter frozen for over a year, and it still had the truffle aroma when I pulled it out of the freezer.

I actually think the infusion method adds a lot more flavor/aroma than adding pieces of truffle, but the pieces are clear evidence that what you bought actually came in contact with real truffles--it's pretty much just marketing.