I doubt Nobel Prize winners procrastinate on HN as much as we do. They are probably busy making things happen.
The typical HN reader, by contrast, finds many things and almost everything and anything (as PG might say) interesting. [1]
"If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity. "
This is not to say that Nobel Prize winners aren't curious of course they are. But somehow I doubt they are all over the place. I find so many things interesting it's hard for me to stay focused some times with the distractions of what is available at your fingertips.
My point isn't that a Nobel Prize winner would be interested in "physics and society" or baseball or gardening or all three but they would not have a version of ADD (let's call it that for lack of a better diagnosis [1]) which caused them to continually fork on all sorts of things that just satisfied someone's curiosity so to speak. (I also noted in another comment that I found this as well in Physicians who I have known.)
[1] I don't have ADD but sometimes I wonder if there is a version of intellectual ADD.
The xkcd comic describes it as nerd sniping. http://xkcd.com/356/
That said I don't think your one example proves my theory wrong simply because I didn't say that someone couldn't have other interests what I believe I was trying to say is that they aren't "all over the place". The question really is "how many pet topics" do they have I guess. I would just think that that type of brain has to be more focused.
I've also noticed this with Physicians as well (anecdote of course). I've told them different things and they tend to react as if "wow who would know that or think of that" type of stuff. Because my brain (and I'm not even saying this is an advantage) tends to be all over the place in what I find interesting. So maybe it's a matter of degree not an absolute that can be measured.
That kind of discussion (and much worse) often occurs at the breakfast table on many farms without anyone ever batting an eye.
For example "hey, do you know what kind of animal that foot on the front steps is from? There's a blood trail behind it but the cats aren't very interested."
I also suspect that reaching a science-Nobel-worthy breakthrough requires not just more years but more-focused work. Feynman may simply have been an exception, but he might also represent something that was possible then but has become less possible with each passing year.
FYP.
Seriously though, I expect you're true that most Nobel winners are highly focused. But I expect so are many (not most) regular readers of HN.
There are probably on the order of a thousand living Nobel Prize winners in the world, or one in seven million or so. In developed countries, where most of HN's readership would come from, the concentration should be higher. My understanding is that HN's regular usership is in the 6 figures, so most likely no Nobel Prize winners there. Not sure how many users have ever registered to HN though. Perhaps there is an HN account belonging to a Prize winner...