Five to 10 years ago, independent bloggers used to be able to get by on internet advertising, like the broadsheets of yore. But that changed quite quickly, and for two big reasons: Facebook and Google. They now gobble up the vast majority of internet advertising dollars — about 85 percent, as my colleague Jeff Spross writes — and a great many media outlets have been forced to move to direct subscriptions or other business models. Google and Facebook manage this because they are platform monopolists.