An HTML file is just an ordinary text file which contains the HTML tags that the HTML browser will use to display your document. Default file extensions for HTML documents are HTML or HTM but you can use any extension for your purpose. Mailing lists offers ways for people with common interests to send messages to one another. Unlike newsgroups, mailing lists e-mail a separate copy of the message to all people subscribed as recipients on the mailing list. Mailing lists have their own email address with which you send an email to and any message sent to that address will be re-mailed to all people on the list.
All mailing lists have their own list owners.
Lists owners or moderators are the ones responsible for the overall maintenance of the mailing list. Most administrative addresses are often processed by a list server programs. Mailing list administration is either done manually or automatically. To subscribe to manually-maintained lists, send a message to the mail list address and indicate your request to join. After joining a mailing list, all messages sent to the mailing list address will automatically be sent to you.