This is a new design with the wide page layout. For more details, please visit the Narrow Layout page, but the main difference between these two layouts is that the main content of this layout is not limited by the margins of the header and the footer. In other words, the main content spans from right to the left edges of the browser or the device you are currently using. Also there are no margins on either left and right sides, so they should be defined as necessary.
Also, both formats may include a subtitle as shown on this page: "New Program Series: Jazz Across America" utilizing 2 font styles. This subtitle is defined as H2 tag, which has a second importance of the search engine keywords ranking (after the title), therefore should be used accordingly.
This format is useful for the home page and other pages with significant amount of the content and/or pages with the large images; or heavily formatted content, such as tables, schedules, playlists, etc.
See also the Narrow Layout of this new design.