What is CPM in Advertising & Why Digital Advertising Still Runs on it?

If you’ve spent time in ad forums, Discord groups, or even Slack channels, you’ve probably seen it: “What is CPM in advertising and why are we still using CPM ads in 2025?” It’s a common question, and fair enough. With CPC, CPA, CPL, and every other performance model, CPM can seem a bit… ancient. But …