I ask questions like this a lot, and that is not at all what it's about. The motivation for asking what somebody is trying to do is that I don't know a good answer to the question they asked, but I have a nagging feeling that their question might actually be reducible to a different question that I can answer easily. It would be presumptuous to just answer a completely different question, though, so I ask for clarification whether this is in fact the context that it looks like. To put it another way, they're asking "How do I hit glass with stone without breaking it?" but what they actually want to know is "How do I get the lid off a beer bottle?" The fact that they currently believe removing a beer lid involves striking the bottle with a rock doesn't necessarily mean that answers along those lines are the most helpful. But I can't be sure when I see that question whether they are thinking about a beer bottle.

For example, yesterday a guy asked a rather complicated question about hacking the Objective-C runtime to replace a class in the inheritance tree. But from his question, I was able to infer that what he actually wanted to do was globally change a class's behavior. So I answered the question that I read between the lines. His response was, "Oh, yeah, I don't know why I didn't do that to begin with." In that case I felt sure enough to answer without asking, but in other cases I'm not as confident whether this is actually a different question in disguise.

Sometimes there really is a better way to solve their problem. Sometimes, the problem they have can be guessed reasonably accurately, and solving it for them is useful. I've found such answers helpful in the past.

I've replied to "does anyone know where the nearest ATM is?" with "the pub we're going to has no card transaction fees or minimum spend". It doesn't necessarily solve their problem, but there's enough chance that it does, that I feel it's a useful thing to say.

I wouldn't assume it means they know the answer. On the lists I'm on, it usually means "I have no idea how to answer this question directly, but if you give me more context maybe I could answer a broader question that gets you what you want."