There are many online resources for genealogists, some are free, some are available through a Duke University Library subscription, and some have hybrid model where basic access is free with premium subscriptions available.
Here are some of our favorites:
Ancestry for Library Edition (Available to the Duke community through NetID and password. Use this link and authenticate through Shibboleth, Duke Health employees should turn off Zscaler.)
Contains coverage of the U.S. and the U.K., including census, vital, church, court, and immigration records, as well as record collections from Canada and other areas. A collection of more than 4,000 databases and 1.5 billion names including U.S. federal census images and indexes from 1790 to 1930; the Map Center containing more than 1,000 historical maps; American Genealogical Biographical Index (over 200 volumes), Daughters of the American Revolution Lineage (over 150 volumes), The Great Migration Begins: Immigrants to New England, 1620-1630, Social Security Death Index, WWI Draft Registration Cards, Federal Slave Narratives, and a Civil War collection.
FamilySearch (basic access is free, subscription to full access available)
Database with billions of records provided by the Church of Latter Day Saints. This database includes Ancestral Files, the International Genealogical Index (IGI), Pedigree Resource Files, and Web Sites. Also includes a Directory of Family History Centers and other useful information.
National Archives Resources for Genealogists (freely available)
Contains answers to many of the preliminary research-related questions you might have.
National Archives Vital Records (freely available)
Vital records most commonly refer to records such as birth and death certificates, marriage licenses and divorce decrees, wills and the like.
Library of Congress's Chronicling America (freely available)
Search America's historic newspaper pages from 1777-1963 or use the U.S. Newspaper Directory to find information about American newspapers published between 1690-present.
Cyndi's List of Genealogy Sites on the Internet (freely available)
A comprehensive, categorized & cross-referenced list of links that point to genealogical research sites online. A trusted genealogy sitt for more than 25 years.
Ellis Island Passenger Search (freely available, can hire expert with donation)
Database of more than 22 millions passengers and ships' crews that came through Ellis Island the the Port of New York between 1892 and 1924.
USGenweb Project (freely available)
The USGenWeb Project hosts volunteers providing free online genealogy research in every state and county in the United States. The Project is non-commercial and fully committed to free access for everyone.
WorldGenWeb (freely available)
The WorldGenWeb Project is a non-profit, volunteer-based organization dedicated to providing genealogical and historical records and resources for world-wide access.
BillionGraves (freely available, some features by paid subscription)
BillionGraves is the world's largest resource for cemetery data. Memorials generally include birth, death and burial information and may include pictures, biographies, family information and more. This resource links to MyHeritage for fuller genealogical information.