You've probably noticed that when an especially big news story happens, newspapers, and news websites don't just produce one story about it but often many different stories, depending on the magnitude of the event.
These different kinds of stories are called mainbars and sidebars.
What Is a Mainbar?
A mainbar is the main news story about a big news event. It's the story that includes the main points of the event, and it tends to focus on the hard-news aspects of the story. Remember the five W's and the H - who, what, where, when, why and how? Those are the things you generally want to include in the mainbar.
What Is a Sidebar?
A sidebar is a story that accompanies the mainbar. But instead of including all the main points of the event, the sidebar focuses on one aspect of it. Depending on the magnitude of the news event, the mainbar can be accompanied by just one sidebar or by many.
Let's say you're covering a story about the dramatic rescue of a boy who has fallen through the ice of a pond in winter. Your mainbar would include the most "newsy" aspects of the story - how the child fell and was rescued, what his condition is, his name and age and so on.
Your sidebar, on the other hand, might be a profile of the person who rescues the boy. Or you might write about how the neighborhood where the boy lives comes together to help the family. Or you might do a sidebar on the pond itself - have people fallen through the ice here before? Were appropriate warning signs posted, or was the pond an accident waiting to happen?
Again, mainbars tend to be longer, hard-news oriented stories, while sidebars tend to be shorter and often focus on a more feature-y, human-interest side of the event.
There are exceptions to this rule. A sidebar on the dangers of the pond would be a very hard-news story. But a profile of the rescuer would probably read more like a feature.
Why Do Editors Use Mainbars and Sidebars?
Newspaper editors like using mainbars and sidebars because for big news events, there's too much information to cram into one article. It's better to separate the coverage into smaller pieces, rather than having just one endless article.
Editors also feel that using mainbars and sidebars is more reader-friendly. Readers who want to get a general sense of what has happened can scan the mainbar. If they want to read about one particular aspect of the event they can find the relevant story.
Without the mainbar-sidebar approach, readers would have to plow through one huge article to try to find the details they're interested in. In the digital age, when readers have less time, shorter attention spans and more news to digest, that's not likely to happen.
An Example From The New York Times
On this page, you'll find The New York Times' main news story on the ditching of a U.S. Airways passenger jet into the Hudson River.
Then, on the right side of the page, under the heading "Related coverage," you'll see a series of sidebars on the accident, including stories on the quickness of the rescue effort, the hazard that birds present to jets, and the fast reaction of the jet's crew in responding to the accident.