They compete in the same market (digital ads) but provide different utilities for the consumer, hence aren't competitors when it comes to user attention. Google

They compete in the same market (digital ads) but provide different utilities for the consumer, hence aren't competitors when it comes to user attention. Google provides a search engine, GSuite stack and other free products, YouTube, etc. Facebook provides a social network and networks to connect with their families. There isn't a meaningful competitor for either in either space. And most companies simply retain two marketing budgets - one for Facebook and one for Google.