Q. What is Usenet
A. Usenet is a worldwide discussion board consisting of user driven messages on various topics and subjects.
Q. What are Newsgroups?
A. Newsgroups are the discussion of those topics and subjects which are organized into hierarchies making it easier to find what you are looking for. An example of a newsgroup comp.* is a newsgroups in Usenet that facilitates discussions about computers, programming etc and can even offer you technical support to your questions. Having a software or database bug you just can't figure out, you are bound to find a newsgroups to help you figure it out. A newsreader is required to participate in these newsgroups