Just heard about a new way to invest in stocks - based on how new products sell

According to Smarkets.com

Smarkets work like…

Each new product added becomes a "stock".
If a product’s Amazon’s sales rank improves, its stock price goes up. And vice-versa.
Traders buy, sell, short, and cover.
Products are grouped with tags and compared to other tag groups. (…more help)

This may be another way to get into investing - new stock market.   Of course, there will be "metrics" for this as there always are for Financial Transactions.