I'm a big fan of continuing to research a problem after a question has been asked. It shows initiative on the part of the asker. At the same time, I find it incredibly annoying when people ask a question only to answer it themselves less than 10 minutes later. This shows that they really weren't looking hard enough and, in my opinion, fills the site with unnecessary spam.
A good example is this question from yesterday. The author asked the question, then answered it 6 minutes later.
Ironically, I know this question would have probably been answered with a link to let me Google that for you if asked on the regular WP forums - a practice that's been degrading the quality of the site lately.
So here's the question: what do we want to do with this kind of q&a on the site? Should we encourage people to search a minimum amount of time on Google before asking? Should we discourage answering your own question the same day you've asked it?
My concern is that this author won't accept another as "the answer" since he's already answered it himself with the correct solution. Anyone else (i.e. John Bloch's answer 1 minute later) will end up appearing as a copy-cat response.