One cool aspect of the public nature of the web, is that you can watch some of the most effective people up close. For an aspiring hacker, this leads naturally to measuring oneself against their accomplishments, or to be more exact, comparing what you've done to what they'd done at your age, or vice versa. I've done this, with some mixed results.
For example. Aaron Swartz is a number of years younger than I, and he has, among other things, just released his first web framework. On the other hand, I've five years left before I have to achieve the like of Ruby on Rails creator David Heinemeier Hansson.
Now one could ask whether I actually expect to do so. I honestly don't know what I'll do these next few years, but I do know I won't do much if I don't aim to do much. That said, there's a refreshing familiarity to the thoughts I read in Hansson's "Loud Thinking," particularly the early years. What more indication do you need? ;-)