If a company takes control of the product before selling it, it reports the full price as revenue (gross). If it only connects a buyer and a seller, it reports just the commission (net). The economics can be identical while the reported top line differs by a factor of ten.
This is why gross-merchandise-value and revenue are different numbers for a marketplace, and why comparing a gross reporter's price-to-sales with a net reporter's is meaningless.
Example: Northwind Marketplace processes $2.0B of tool sales and keeps a 9% commission. Reporting net, revenue is $180M. A rival that buys and resells the same $2.0B reports $2.0B of revenue on a similar $180M of gross profit.
Related: revenue