Usenet is Public
Anyone interested in the subject can read your article, you have no control over who all reads your article. Anyone who wants can reply to your article, either privately by mail, or publicly with an article.
Usenet is a mass medium
You reach an undetermined but large number of people, just as you do with newspapers or television.
Usenet has no central control
Unlike television and newspapers, Usenet does not have an editor who reviews your article before it is published. Thus, there is also no central media owner. Responsibility for content can only be assigned to the author.
Usenet has no owner
Each news server is physically owned by the corresponding provider. 
However, a news server alone is not Usenet; Usenet is only the sum of all news servers, and is created by the cooperation of the news servers (and thus the providers) to share and copy the new articles with each other.
Usenet can only exist through general tolerance of the topics.
For practically every topic, there is a majority of people who think that discussions on that topic are pointless, blasphemous, criminal, moronic, or perverse, and thus unacceptable. But because this is true for all topics, the only chance to be able to discuss even the topic that is important to you is to let all other topics exist as well. The nice thing is that you don't have to read those topics that are unacceptable to you and certainly don't have to join in the discussion, you can easily ignore those topics.
Usenet is distributed worldwide
National legislation clearly refers to the sphere of influence of the respective state. Usenet, however, is now an international medium whose content is distributed worldwide within seconds. Unlike physical objects, Usenet has no defined interfaces at national borders. This means that it is almost impossible to control cross-border information, which has both advantages and disadvantages:
While on the one hand this allows a free exchange of opinions without state censorship, on the other hand information that violates the laws of a state can be published in that state. National legislation has little effect in this medium; only common, international legislation can intervene effectively here.
Usenet enables anonymous publications
In Usenet itself, every article is traceable, it is only a question of the means used. It is a misconception to think that just because you don't add your name, you are anonymous. But there are so-called anonymous remailers that allow you to publish articles really anonymously.
This anonymity is important in some areas. The classic example of this is self-help groups. It may very well hurt people if it becomes known that they have or had a problem there. Here anonymity offers the possibility to discuss it publicly.
More details can be found under the link: how to find movies on usenet