Reputation comes slowly at StackOverflow

I've been a user of StackOverflow for 18 months now; it's an interesting and useful site, and I enjoy participating.

I don't put a lot of time into the site, but I do visit almost every day, and generally interact in one way or another.

But after 18 months, my reputation is only slightly more than 500.

And yet, though StackOverflow as a institution is only a few years old, there are users with hundreds of thousands of reputation!

According to the privileges list, I have about 60% of the privileges, so I guess I'm making progress.

I'm not sure why it matters; I'm just sort of noticing it.

But, anytime there's a measurement, and I'm one of the people being measured, I'm always intrigued...