<p>I come down strongly in favour of providing quick-and-dirty answers, given two conditions: i) the question is not a bad one (in which case, close and/or downvote), and ii) the alternative is giving no feedback of any kind (comments asking for clarification are therefore an exception). As for why Q&amp;D answers are worth providing:</p>

<ol>
<li>Someone out there needs help. A partial answer may quickly
address their main point or put them on the path to solving it
themselves. No answer is no help at all (unless you're giving feedback in
comments, of course). This reason doesn't apply if the goal is to
develop a shared library of great answers. In practice, I think many of us are also motivated by a general desire to help people with problems. So I'm happy to write a short answer to help out, even if it's not going to be a general reference in the future.</li>
<li>The voting mechanism exists to sort out the bad from the okay and
the good. If a Q&amp;D answer I provide is unhelpful or misleading,
people are welcome to downvote it. And if it gets upvotes, it's a
signal - if a noisy one - that it was helpful. This is partly why I
think we should be downvoting more in general - it helps send a
clearer signal.</li>
<li>Providing a quick answer is not a barrier to someone providing a
more comprehensive or better one.</li>
<li>You mention knowing "a little about a lot, and a lot about a little". In contrast, I know a little about a moderate amount, period. But this little is <em>still</em> enough to be helpful for many simple questions. If I, and other novices like me, can take care of the basic questions, then the true experts can spend their time crafting the great answers that will form the general reference we all desire. It may not be the most efficient use of their time to deal with the basic questions.</li>
<li>Related to the previous point, if this type of short answer were more common, it could motivate broader participation - with the end result that we eventually have more people writing the great, detailed answers too. As a newcomer, it was difficult and time-consuming to find a question that was a) well-formulated, b) not a duplicate, and c) within my ability to answer in a detailed manner. I suspect that if the community viewed Q&amp;D answers positively, that would make it easier for new users to start contributing to the community.</li>
</ol>
