FEES vs REVENUE

I see many people use these two interchangeably, but they measure fundamentally different things, and it's quite important to know the difference so you evaluate protocols/chains properly.
Fees are the total amount users pay to interact with a protocol: every swap fee, every unit of borrowing interest, every dollar spent on gas.
It is a measure of gross economic activity; it tells you how much demand a protocol is generating, nothing more.
Revenue is the portion of those fees the protocol itself retains, after paying out the parties who actually did the work of providing the service: liquidity providers, lenders, validators, or stakers.
It reflects what accrues to the protocol's treasury or token holders, very similar to what "revenue" means for a traditional company.
A protocol like a decentralized exchange can generate enormous fee volume while passing nearly all of it through to liquidity providers, leaving very little for the protocol itself. Meanwhile, a lending protocol's headline fee number includes interest that mostly flows to depositors, not to the protocol.
For example, Uniswap generated about $1.23 million in fees in a single day, but its actual revenue was only around $89,250, because nearly all swap fees go to liquidity providers, not the protocol.
Similarly, Aave searned roughly $915,270 in fees but only $123,400 in revenue, since most of that interest goes to lenders.
If you just need sth to remember:
High fees can simply mean high usage passing through to someone else.
Revenue is the number that tells you what the protocol is actually earning for itself.
You're welcome.