FamilySearch

It's astonishing that FamilySearch, which is mostly administered by volunteers, has been able to upload more than 6 billion recordings since it first launched in 1999. There is no built-in technology that searches the data for you and identifies probable matches, so finding your family's documents will require some detective effort in contrast to the aforementioned methods. However, you can look through records like census information, military records, birth, marriage, and death certificates.

The Church of Jesus Christ of Latter-day Saints, which runs the website, sees publishing these records as one of its responsibilities. There is no commitment to align with these beliefs though, so you can enjoy the records without any pressure to get involved with that side of the service. Given that it's a free site, a few components are missing, and it seems a little stale.

Website: familysearch.org