Think of the OP as your immediate target, then the rest of the blender users in the world.
At first the reaction will be from the OP, over time more people will see it, and you very likely will get more positive comments.
Now because the OP is the first target, the OP is the one that dictates the response you get - good bad, or none.
Keep in mind what kind of question you are answering, is it a simple thing where the OP glances at your answer, presses the button you told him to and then never comes back? Or a much more detailed step by step answer where the OP may have further questions?
In a few cases, new users, simple answers, or migrated questions, I don't expect to hear back.
I can definitely relate to your feelings, after writing a long answer just to have it be silently ignored, feels almost like a waste of time.
But it is not.
Even if the OP never sees it, hundreds or thousands of other people will see it and probably learn something from your answer.
Try not to get discouraged (even from a 0 UVed good answer), there are just some times where you will never hear back from the OP - no comments or any accept vote.
That just makes the positive comments you do get all the more special.
To all users reading the site, whenever you find a post that helped you, UV it.
It is like giving the OP a hand shake and saying "thanks." It's just a small thing but it helps keep this site going.