I wonder how many people do hold and drag the scrollbar, I am so used to scrolling using a touchpad on Mac and mousewheel on PC, so I never even touch a scrollbar.
I've done many user tests and training sessions only to inwardly wince every time the user painstakingly does that. (And this on their own hardware, with their own mouse they use every day at work.)
After you explain it, they say "wow, that's neat." And then promptly forget it and start dragging the scrollbar again.
I was until recently a devoted scroll-wheel-user. But I'm starting to see the first signs of arthritis in my fingers (far too early if you ask me) and scroll wheels are becoming increasingly uncomfortable.
I've been surprised to find that dragging an old-fashioned scroll bar is actually a faster and more accurate than the wheel if you're scrolling by more than a page or so.
It is very inconvenient on a large page like this, should you need to quickly move up/down to read a related comment. If you know it, dragging the scrollbar, on the other hand, is quick to land you in the approximate target region.
