If you are going to give feedback to a new user a downvote may not be clear, and I would go as far to say, is never clear. Please leave them a comment and explain the site, you can flag as Not an answer for a moderator or higher rep users to clear out the post with a delete and have a comment explain what they have misunderstood.
A good comment to leave might be along the lines of:
This forum is not like other forums, there is already an answer for this question and the way to support it is up voting. The reason you cannot upvote is because you have not yet attained the reputation required to do so, a rough estimate of both expertise and knowledge of the site. Please try to add new answers other places or ask questions you have. If you have any confusion about the site, visit the [FAQ](http://electronics.stackexchange.com/faq)!
I put a space in between FAQ and the link so that you can copy paste and remove it for a working link.