Do I need to apply to these networks separately?
For Header Bidding Mediation, yes. You are connecting your existing accounts. If you do not have an account with a specific network, you must apply to them directly before you can add them to Ezoic.
Is this the same as AdSense Mediation?
No. AdSense Mediation is specifically for linking your Google AdSense account. Header Bidding Mediation is for other third-party exchanges (like Rubicon, Pubmatic, or 33Across).
Does Ezoic take a cut of mediated revenue?
No. 100% of the revenue generated through your mediated partners is paid directly to you by those partners.
What is the benefit of adding these if Ezoic already has partners?
While Ezoic has thousands of partners, your specific site might have a high direct-demand value with a specific network. Linking that account ensures that if they are willing to pay more than Ezoic's partners, they win the impression, maximizing your EPMV.