You're right, most people present the best them, as they see it, to the online world, and some just act like themselves online, "Ooh a piece of candy, ooh a piece of candy." For those who act true-to-self, the parameters (locations and actions) the internet provides for people to bounce around in, never expose that deep of an image of a person.
This also occurs during real life interactions as well. Few are completely genuine even when looking at them directly in the eyes. People omit information, some embellish, and others downright lie to make themselves appear the best possible.
Have you ever had a conversation with someone whom you connect with deeply and for a mere second you can see the true them? You can almost imagine them as a child because their truest essence comes out for a second during a laugh, or a cry. The truest external example of self.
We're a long way from software being able to grasp that level of understanding of a single person. Even if, it would be hard to categorize and sell ads to a person based on that. In other words, I hold out hope for the resurgence of appreciation of the other.