In what year was Tumblr launched to the public?

Tumblr was launched to the public in 2007.

David Karp founded Tumblr in New York as a short-form blogging platform, often described as a tumblelog service. The site was designed for quickly publishing text, photographs, quotations, links, audio, and video without the complexity of a traditional blog. Its public launch helped establish the dashboard-and-following model that later became central to the service.

Tumblr’s early growth was driven by its simple publishing tools and highly shareable posts. Reblogging, which became one of the platform’s signature features, helped content move through follower networks and encouraged remixing and commentary. The platform soon became especially important to online communities focused on art, music, humor, fashion, and fandom.

The year 2007 is sometimes confused with 2006 because Karp and early collaborators tested Tumblr privately before its public release. That earlier development period explains why some accounts or archived posts may predate the site’s public launch, but the accepted launch year is 2007.