If you’re like me, the concept of digital-only goods is a bit confusing. Like, I understand the value of writing a piece of software. You build it, it’s completely digital, and it can be used for specific purposes.

Cryptocurrency (like Bitcoin) comes close in my head to this kind of thing. It’s a little hazier than something you could put on a flash drive and give to a friend. But it’s real money that can be spent on real goods and services. Heck, you can buy Bitcoin at some ATMs now.

But NFTs, or Non-Fungible Tokens, are a different matter. Something that is fungible can be replaced by something identical or of equal value. You could trade a $100 bill for five $20 bills and have the same thing. Non-fungible is the opposite.

For example, anything that is a unique feature of an item that makes it different than other identical (in every other way) items makes it non-fungible. If you loaned your brother your car, he couldn’t bring you back a different car, even if it was worth the same amount of money. Maybe you left a picture of your daughter in the visor. Maybe you have a Flying Spaghetti Monster bumper sticker.

When you buy an NFT, you are theoretically the only person in the world with that exact thing.

A new report from The Guardian shows that 95 percent of those holding NFT collections — which were all the rage two years ago — are holding worthless investments. That’s 23 million people. Why are they worthless?

There are a few reasons. First and foremost, there’s very little demand for such things. Maybe they’re ahead of their time, or maybe people just don’t quite understand the concept, but those monkey pictures you saw all over Twitter in 2021 are worth nothing now.

The second reason lies inside the first: If you saw that monkey picture on Twitter and know how to right-click, you could just save the picture to your own computer. If all the value of an item lies in its uniqueness and you make a duplicate, it loses its value.

Even Melania Trump ventured into the world of NFTs, creating a line called “Melania’s Vision” that provided artwork of the former First Lady’s eyes. That collection is completely without value now. And yet Melania still made NFTs of the line of Christmas ornaments she’s hawking this year.

Here’s a tip: Opt for the one that hangs on the tree.