Try using one of those free email addresses for posting to Usenet, and your regular service only for private communication. A name of some sort is much more personable than a string of numbers. It's best to put it in the headers too, if possible. Please don't post from multiple accounts, especially to answer your own posts . When you follow up to a public message, don't email a copy to the original author unless you make it clear you have done so.
Most people check email and respond to private messages first.
When the person later finds out that the message was also publicly posted, don't be surprised to find that the public response is not as sympathetic the second time around. If someone sends you a private message, it is a breach of confidence to announce it or post a public response. An exception to this might be an informative response from a company and manufacturer that clarifies an issue for the group. Even so, it isn't likely to inspire trust. Interaction Give a message time to propagate.