You've seen it before, even if you didn't know it. The sales page screams "Buy now! Only 100 23 copies left!" Then you come back a month later and it still says "Buy now! Only 100 23 copies left!" Either the product ain't selling or somebody's lying.
One of the latest big sellers on ClickBank is called Traffic Anarchy. Supposedly, only 350 copies were going to be sold. But is that true? Let's check.
We can't log into the seller's ClickBank account to see how many sales they've made. And frankly, there's no way to know exactly how many copies were sold. But ClickBank does publish a number that's guaranteed to be less than or equal to the actual number sold: gravity.
"Gravity" is based on the number of affiliates who've made a sale of a product. (for the exact formula, see my explanation of how ClickBank calculates Gravity). Each affiliate has sold at least one copy of the product, so the actual number of copies sold cannot be less than the gravity score.
Here's a graph of the gravity score for Traffic Anarchy (from Instant Affiliate Accelerator):
To be precise, Traffic Anarchy's gravity, as of last night, was 591.03. So we know that at least 592 copies have been sold.
I'm no lawyer, but that looks like false advertising to me.