If I think the message may be interesting to another person, I will generally feel free to forward it. I will feel free to lift pieces or paragraphs or .signatures, often without attribution. News can take a week to circle the globe, especially if it gets passed over a few phone links. News articles are frequently reposted to other newsgroups.
Many people routinely archive newsgroups of personal interest.
Some people have very fancy filters to select news articles they are likely to want, or to send to friends. This could become a commercially useful idea, especially as we become saturated with news. All of these strike me as reasonable use.