The existing answers to this question are old, and no longer reflect the current mindset of the team or community.
As Stack Overflow has grown, the number of trivial questions it receives has increased, causing problems for the site's signal-to-noise ratio. As a result, people have become less tolerant of such questions than they were in 2009.
In February 2011, Jeff followed up a podcast with a blog post that asked whether some questions were just too simple for Stack Overflow. It doesn't explicitly come out and say that the answer is yes, but it does close with this:
Allow your Q&A community to fill itself with enough “General Reference” type questions and you’ll soon find no experts there at all.
The team is experimenting with using "General Reference" as a close reason on some sites, with great community support. As of this writing, it hasn't been considered successful enough to be deployed network-wide, but it also hasn't been considered a failure, per Jeff.
Apparently, this was discussed in the week before I posted this answer. See Has a consensus been reached on whether or not some questions are too simple? The answer from Jeff there boils down to "sometimes."