Zuckerberg injects himself into the vaccine controversy with his newborn

"Doctor's visit -- time for vaccines!" Zuckerberg, 31, wrote below the picture of Max. By Tuesday, the image had more than 3.2 million likes and over 88,552 comments. It also had been shared 33,149 times. If you're not up on Facebook metrics, let me just say that's a lot.

Zuckerberg has turned his Facebook profile into a soapbox. That's notable. On any given day, about 47.7 million Facebook followers check out what he has to say.