Listing Enhancement Fraud
Even pressing refresh a few times should be enough to tell you that the Marketplace listing enhancement function provides only a limited number of promotional slots, and that once they're filled, paying for one of the slots will do nothing for you. That's why you see the same listings pop up again and again out of thousands of possible listings.
That this is true is easy for any merchant to prove by:
1) making 2 identical listings, 1 with maximum listing enhancements, and 1 with none
2) waiting until the end of the listing enhancement period
3) checking the view rates for the 2 listings to see if there is any statistically significant difference.
Selling a limitless amount of a limited service is actually a crime, and Linden Lab has probably stolen no less than a million dollars from merchants over the last 10 years.
This is not a bug, a data entry problem, or a bad integration test between 2 pieces of good code.
This is a basic feature built into the website by Brooke Linden, who we now know was a person with zero integrity.
If you politely point any of this out to Linden Lab, your reward for trying to help them fix their system is that they will invent excuses to close your Marketplace store so you can't collect any incriminating data, and they will ban you from the forum to deter you from sharing any data you already have.
How do I know?
It happened to me.
Second Life resident Josh Susanto