Not only is adtech virtually unregulated compared to financial exchanges, it's also immensely more fragmented, and ad networks like Google AdSense are tremendously sticky once they've been exclusively integrated on the long tail of millions of publisher sites. See https://lumapartners.com/content/lumascapes/display-ad-tech-... for all the parties involved. There's a lot less transparency for all parties involved (see the work of , and arguably some version of an SEC for adtech is long overdue. If ad exchanges were operated with the transparency of broker-dealers, initiatives like https://checkmyads.org/ wouldn't need to exist.