Newsgroups are not a part of Netscape. Internet is a network of computers. It is best to think of internet as a community of people with computers. People use the internet to communicate. There are several processes that are used for communication.
Electronic mail is used to send messages from one user to one or more specific users.
FTP or file transfer protocol is used to transfer files from one computer to another. Newsgroups are used to post messages and read other people's messages. Think of newsgroups as a central bulletin board for messages and notes. Messages may be commentaries, questions, or response to previous postings. In moderated newsgroups, someone screens the messages and then posts the suitable ones.