Terse responses can sound rude. You don't have to be verbose, but a few extra sentences will go a long way to ensure that you don't hurt someone's feelings. Perhaps the sender was in a big hurry and didn't have time to explain everything fully. What may be worse than a terse response is no response at all. Don't expect an immediate response to your email or news queries.
People tend to get bogged down in unread and unanswered electronic correspondence.
You might get an answer in five minutes but it also might take five days, or weeks. Just because you don't hear from someone immediately does not mean she or he thinks your message was unimportant. Always Point a Loaded Mailer or Newsreader at the Ground. Just as you shouldn't drive when you're angry or upset, you shouldn't send responses to email and news articles when you're mad at someone. A delay may seem frustrating, but chances are that when you come back later to read your response, you'll be glad you didn't send it.