Online public libraries, such as the Digital Public Library, are online depositories of digital writings, art work, music, pictures and videos. These digital goods are available for use by the public across the globe, often for free. Some traditional brick-and-mortar libraries, such as Wallingford Public Library, also provide online resources.
The Digital Public Library of America has a search engine for locating specific digital books, pictures and videos. Users can also browse categories, which include Primary Source Sets, Maps, Exhibitions, Timeline and Bookshelf.
The Bookshelf category enables users to search by participating libraries, language, date, subject or location. Primary Source Sets contain digital images of original documents and photographs of period artifacts. As of 2015, sets include Road to Revolution: 1763-1776, "A Raisin in the Sun" by Lorraine Hansberry, Early Chinese Immigration to the US, Mexican Labor and World War II: The Bracero Program and The Lewis and Clark Expedition.
The Exhibitions category contains photos and writing on select historical and cultural themes. As of 2015, the category includes A History of US Public Libraries, America during the 1918 Influenza Pandemic, and America's Great Depression and Roosevelt's New Deal. The Maps category has free images of locations and documents. The Timeline category enables users to search for events by date.