Comparison of Platform Take Rates

Peter Cramton asked three questions of Perplexity.AI (Perplexity.AI) about platform take rates. 1) Companies often take a percentage when the platform they provide to others is used for financial transactions. For example, Substack takes 10% and its payment processor, Stripe, takes 2%. Google Ads takes about 40% from sellers and buyers combined in the Google Ad Exchange. What are some other examples of "take rates" across industries? 2) Why are some take rates higher than others? 3) Is there any evidence that Google's high take rate is enhanced from its anti-competitive behavior?
The answers produced a six page pdf including citations. He then asked Google Notebook LM to create a podcast about the answers. Here is the podcast. Enjoy.