Facebook published a quietly groundbreaking admission on Friday. Social media, the company said in a blog post, can often make you feel good — but sometimes it can also make you feel bad.

Yes, I should have warned you to sit down first.

This is one of those stories where what’s being said isn’t as surprising as who’s saying it. Facebook’s using a corporate blog post to point to independent research that shows its product can sometimes lead to lower measures of physical and mental well-being should be regarded as a big deal. The post stands as a direct affront to the company’s reason for being; it’s as if Nike asked whether just doing it may not be the wisest life goal after all, or if Snapple conceded it wasn’t quite positive that it really was the best stuff on earth.

Consider Facebook’s place in the social-media firmament. Facebook — which also owns Facebook Messenger, Instagram and WhatsApp — is the world’s largest and most profitable social media company. Its business model and its more airy social mission depend on the idea that social media is a new and permanently dominant force in the human condition.

So far, that idea has proved unwavering. Facebook’s leap into the ranks of the world’s most valuable companies less than 14 years after its founding can be attributed to this simple truth: Humans have shown no limit, so far, in their appetite for more Facebook.