[btmoney06]

If we’re focusing on ad buyers instead of users, then why isn’t the relevant market just all “advertising companies” (instead of social media companies)? When you compare Facebook to other advertising companies, their market share dwindles. Google holds the advertising throne.

[onion2k]

Google's 2019 revenue was $162bn. They're only twice as big as FB by that metric, and they have far less than twice the market share.