Honesty is the best policy
One of the inter-generational differences (whether it's the metaphorical cart the or horse in this argument I don't have the insight to say) is attitudes towards honesty: telling the truth - whatever "truth" turns out to be.
One of the many throwaway lines in the BBC sitcom Just Good Friends (other than the innoculation classic: "didn't you feel a prick?" "Well, Penn, I was a bit embarassed") was Penny's admonishing Vince for telling lies and getting the reply "That's because I'm a liar" and after that the whole topic was dropped and the story moved on. Vince tells lies: it's no big deal.
These days, it seems, that "being a liar" doesn't mean telling people that it's "black" when really it's "blue". But that lying now means not volunteering every single piece of relevant, or otherwise, information at the earliest opportunity - what used to be called "blabbing". Worse than that: being caught lying (telling actual black is blue untruths) is portrayed as being such a heinous crime that the very thought of it is, well, unthinkable. So much for "ooops, you got me" and brushing it aside.
In such an environment, where information is offered freely to or even: forced on a person, how can the generation brought up thinking that way act any differently? They have it drummed into them that giving information is mandatory. That withholding it is "sinful". That you must tell the truth all the time, to everyone, no matter what the consequences for anyone involved.
So when a big, bad, internet giant says "tell us everything", they blab. Age, height, weight, most intimate thoughts, address, list of 50 closest friends, political leanings, shoe size, suspicions about classmates, inside leg measurement, which musician they'd most like to have sex with, hair colour, medical history, favourite programmes and fantasies about their teachers. Hell, even PV-ing is less intrusive.
Whether this is considered "being honest", or is simple naivety, or some sort of catharsis we'll never know. The good thing is that all this data gets lost in the mix along with the billions of other personal records. Fortunately for all these data-givers, so little of it is either interesting or relevant.