A news article is very similar to an email message in that it has both a header and a body. The header will contain information about who posted the message, the subject of the message, a synopsis, and some indexing keywords. The header is used to determine what thread the message belongs to. They provide a forum for contact with academic peers around the world, informing of the latest developments in particular fields months or even years before such information might otherwise become available. Because of the way News works however it has certain further advantages over the email system.
Discussion Lists can often be very high volume.
Once you have subscribed you might find that you are receiving many messages about subjects that are of no interest to you. Mixed in with these may be mail of more relevance, as well as your general 'non-list' email . Because list mail is not separated from your non-list mail this can make your daily management of information more difficult. News is different because it allows you to take part in discussions that are of interest to you while avoiding those that are not relevant. Each topic being discussed is therefore displayed as a separate thread.