Some people think DTrace was built for developers; others think it was for system administrators; some even think it was a tool designed just for Solaris kernel hackers but was so useful we decided to unleash it on the world. All wrong. The user we always had in mind was Solaris user extraordinaire Jarod Jenson. DTrace let's you explore virtually any element of the system -- it's biggest limitation is the user's own knowledge of the system. Jarod has the most diverse and expansive knowledge of enterprise computing bar none; in his hands DTrace seemingly has no limit.
Here's how Jarod works. He gets on a plane and arrives at some gigantic (and usually petulant) corporation. Having never seen the application, he then says something like: I'll get you a 20% win or don't pay me. He sits down with DTrace and gets between 20% and 20,000% (no joke). And from those experiences, he's provided input that's improved DTrace immeasurably (in fact, Jarod hacked up the first version of Java support in DTrace "right quick").
So how does he do it? I only have a very vague idea. Luckily, DTrace user number one is also the latest member of the blogsphere. Check out Jarod's blog to get the latest DTrace war stories. I know I've been awaiting this one for a while, and it's about damned time.