If you're passing through revenue, though, it's often not counted, though it seems to vary by industry and exactly how it's passed through. For example, Paypal's revenue is only its fees on transactions, not the entire volume of transactions that flow through Paypal: its role is a facilitator, and its revenue is what it gets paid for facilitation. The same is true of marketplaces, typically; eBay's revenue is its fees, not the entire volume of purchases that happens on eBay. Groupon arguably has a similar structure, in that they're a marketplace facilitating sales, in which case only their fees should be revenue, not the total volume of goods whose sales they facilitated. But it's arguable.