Our advertising platform, as well as the AdEx Staking Portal are on the Ethereum network. Every single operation executed on the Ethereum network (be it a transaction or an interaction with a smart contract) requires some amount of fees, measured in gas.
When it comes to the platform, gathering earnings from different campaigns, opening a new advertising campaign, etc: those are all operations that need gas to be executed.
Similarly, every time you'd like to create a staking bond or unbond, you would also need gas.
You can check this guide out if you want to understand Ethereum gas and fees better.