Q:

Why do you think responses to good questions come so quickly and with great quality?

I realize that there are questions that don't get quick responses or good answers. But, Why do you think responses to good questions come so quickly and with great quality?

A:

Because the people who have all of the answers are 'trolling'(in the fishing sense) the site for questions they can answer.
Wow, people don't like the word trolling.  What I picture when I see the word trolling is someone sitting on a boat, slowly driving around a lake looking for fish.
So, when I apply that word to the internet, I mean someone continuously looking through the lake site(s) for new fish questions to catch answer.
I'm from Minnesota, so, maybe thats why I have a different sense of the word trolling. (We fish a lot here)

A:

I think there's some human psychology at work here.
I think it's a combination of some of the following factors...

Boost to self-esteem from being seen to have the right answer (in public)
Boost to self-esteem from being perceived as an "expert" on something
The element of competing against your peers (through reputation points)
The good feeling you get when you've helped someone else
The novelty value of this kind of community-based approach (might wear off in time as more similar sites get set up)
The fear of losing out on "easy" reputation points to another user for a question you know something about (accounts for the quick answers, but is driven by the reasons mentioned above)
The fear of looking stupid in front of your peers, some of whom may know you personally in the real world (hence high-quality answers, and the need to keep those answers high-quality consistently)
The pain involved in setting up a new account if you make yourself look like an idiot on the current one

I've just brainstormed a few answers there. It basically comes down to some combination of pleasure/pain linked in with the approval of others...all powerful human drivers.
I think these sites play on that combination of base human instincts pretty well and it's quite easy to get drawn in. Hence you get many "addicts" hopping on every question they can answer, and usually providing well-regarded answers.

A:

Stackoverflow is like playing Monopoly.
I've found that answering quickly is a huge advantage. After several attempts at answering with really good answers, I found I was being outdone by people with rather simplistic (and often incorrect) answers. Amazingly, sometimes the questioner had awarded the checkmark to some lame answer while I was in my second or third paragraph.
I realized you just want to throw something up there quickly to "buy" the real estate. I'll often answer now with a very short sentence. The down side to this is that you can get early downvotes.
Then you upgrade the real estate by building a nice answer on it. The downvoters then look like dorks.

