I agree with this, and I have a couple of additional points I want to make. I hope you'll hear me out.
I haven't yet asked a question on the site, and because of that (and the fact that we're still in private beta), going to the Ask Question link gives me a nice little bit of advice. I've been through something like a dozen private betas, and, for the most part, asked questions on each one, but I still read this little spiel every time around. The last paragraph of it has always stuck with me:
You get the site you build
The first questions set the tone and topic of a site for a long time. Those early questions say a lot about what your community could become. And questions asked during the private beta will be on the front page when potential experts see your site for the first time. So please make those first questions exemplary ones that are interesting, challenging, and worthy of imitation.
If feel like a more generic version of this geared towards both questions and answers would make a really great bit of recommended reading for a private beta. All the posts we write at the moment set precedent, and assuming that we make it out of private beta - not that we should assume that - they'll set the site's course for years to come. If we write awesome answers, then folks down the line will be encouraged to do the same. If we write crappy answers, then we're not going to get anywhere. Fixing that sort of problem is hard.
As an example, I'd like to mention that there's a Stack Exchange site (I won't name it) that I use a lot. I really enjoy writing answers there. I've been on it for several years, although I missed its birth by about ten months. After a while contributing, I looked back at the earliest posts. And . . . many of them were not good. At all. And that's kinda frustrating. Did the site get better? Yes, eventually, because people who were motivated to write fantastic posts came in. But things could just as easily have gone the other way. That's why this is an important issue.
That's Point #1. Point #2 is that the quality of an answer is just as important as the content. I've only written three answers because it's taken me kind of a while to write them. (Part of that is putting in effort; part of that is that my knowledge in certain areas is incomplete.) In two cases, before I'd finished writing, other folks had written answers with, to some extent, the same information.
You could make a case for one of two actions: Posting the answer, or not posting it. In both instances, I chose the former, because I felt that my answer was more complete, or made a different argument to support the conclusions. I say this not to toot my own horn - honestly, maybe my answers were crappy and not worth posting; I'm not an impartial judge - but to try to not discourage people if they run up against a Fastest Gun in the West situation.
Just because someone writes an answer doesn't mean that yours can't be better. Even if they got a bunch of quick upvotes, you still might have something to add. Is this always the case? Definitely not. I've aborted a couple of answers here because even though I was close to finished, someone else wrote something great. And of course an answer that just duplicates another probably isn't worth anything. But I want people to know that there's always room for another answer, so long as it brings something substantial a new to the table - new information, a new view, a new rationale.