From context it sounds like he's talking about the dependence people have on services provided by Facebook and Google. (i.e. a government couldn't pass regulation constraining facebook, since its citizens would rise in upheaval being cut off from their 'drug of choice')

Big data seems to just be a synonym for the big 5 companies he's talking about here. It confused me too at first.

Hum, even so, I don't see him mentioning downsides to that dependance. I understand his argument, but you also can't say it's bad without showing how it is.

Cigarettes causes massive health issues. But coffee turned out not to really cause harm, and we're all addicted and dependent.

I think with the big 5 companies, it's unclear if any harm is being made like with tobacco, or if it's an addiction we can all continue to enjoy like coffee.