As I've started digging through older (more than two months, say) unanswered questions, I've noticed a few in which the OP asked a fairly specific homework-type question, did not get much of a response, and subsequently vanished. In some cases, I suspect that the lack of response was primarly due to the question not being formulated clearly and/or the OP not being familar with markup. However, in many cases a perfectly good answer could be generated.
My question is this: what are people's thoughts about the value of answering these kinds of questions?
On one hand, the OP is almost certainly not going to benefit from a response -- they signed up, asked their question, didn't get an answer and left. Also, the questions I'm thinking of tend to be fairly basic and specific and probably of limited interest to anyone other than the OP.
On the other hand, other users (who may not have been here when the question was originally posed) might be interested in the question and its responses. For instance, I enjoy reading many of the basic calculus questions because that's a course I teach and I appreciate seeing the variety of responses this site generates. Even for fairly specific lower-level homework questions, it's often nice to see different approaches to a solution. It's also entirely possible that another student with a similar question might someday find these questions useful.
I suppose another way to frame the question is whether people see this site primarily as a resource for asking and answering immediate questions, or is there also a place here for archiving interesting or useful questions?