Tumblr (pronounced "tumbler") is a microblogging and social networking website founded by David Karp in 2007 and currently owned by American company Automattic.

Development of Tumblr began in 2006 during a two-week gap between contracts at David Karp's software consulting company, Davidville.

[22] In May 2019, it was reported that Verizon was considering selling the site due to its continued struggles since the purchase[23] (as it had done with another Yahoo property, Flickr, via its sale to SmugMug).

Following this news, Pornhub's vice president publicly expressed interest in purchasing Tumblr, with a promise to reinstate the previous adult content policies.

Automattic CEO Matt Mullenweg stated that the site will operate as a complementary service to WordPress.com, and that there were no plans to reverse the content policy decisions made during Verizon ownership.

[27][28] In August 2024, Automattic announced that it would migrate Tumblr's backend to an architecture derived from WordPress, in order to ease development and code sharing between the platforms.

Tags used as a form of communication are unique to Tumblr, and are typically more personal, expressing opinions, reactions, meta-commentary, background information, and more.

[36][37] With Tumblr's 2009 acquisition of Tumblerette, an iOS application created by Jeff Rock and Garrett Ross, the service launched its official iPhone app.

[68] Multiple researchers looking into Tumblr have found that the website is often used as for community-building and a place to explore identity formation and gender expression for LGBT groups.

Many users felt that the ability to be anonymous, or cultivate the identity they were transitioning to, made posting personal information to the website acceptable and safe.

In July 2013, Tumblr began to filter content in adult-tagged blogs from appearing in search results and tagged displays unless the user was logged in.

In February 2018, Safe Mode (which filters "sensitive" content and blogs) became enabled by default for all users on an opt-out basis.

[75][76] Shortly prior to the announcement, Tumblr's Android app was patched to remove the ability to disable Safe Mode.

[77] The change faced wide criticism among Tumblr's community; in particular, it has been argued that the service should have focused on other major issues (such as controlling hate speech or the number of porn-related spambots on the service), and that the service's adult community provided a platform for sex education, independent adult performers (especially those representing LGBT communities who feel that they are under-represented by a heteronormative mainstream industry) seeking an outlet for their work, and those seeking a safe haven from "over-policed" platforms to share creative work with adult themes.

[84] On the day the ban took effect, Tumblr issued a new post clarifying the new policy, showcasing examples of adult images still allowed on the service, and stating that it "fully recognized" its "special obligation" to serving its LGBT userbase, and that "LGBTQ+ conversations, exploration of sexuality and gender, efforts to document the lives and challenges of those in the sex worker industry, and posts with pictures, videos, and GIFs of gender reassignment surgery are all examples of content that is not only permitted on Tumblr but actively encouraged.

"[85] Wired cited multiple potential factors in the ban, including that the presence of adult content made the service unappealing to potential advertisers, the Stop Enabling Sex Traffickers Act (a U.S. federal law which makes websites liable for knowingly assisting or facilitating illegal sex trafficking), as well as heavy restrictions on adult content imposed by Apple for software offered on the iOS App Store (which similarly prompted several Reddit clients to heavily frustrate the ability for users to access forums on the site that contain adult content).

[77] In January 2022, Tumblr reached a settlement with New York City's Commission on Human Rights, which had claimed that the 2018 ban on adult content disproportionately affected LGBTQ+ users.

[111][114] In addition to these copyright infringements, Tumblr has at times been weaponized by individuals seeking to raise DMCA notices against other sites.

Following a copyright infringement complaint filed on legal archive Lumen and without checking the veracity of the source, Google delisted the Project Brazen article.

[117] On December 3, 2012, Tumblr was attacked by a cross-site scripting worm deployed by the internet troll group Gay Nigger Association of America.

The change was intended to improve the legibility of reblogs, especially on mobile platforms, and complements the inability to edit existing comments.

[119][120] While Tumblr's userbase has generally been received as accommodating people from a wide range of ideologies and identities, a common point of criticism is that attitudes from users on the site stifle discussion and discourse.

In 2015, members of the Steven Universe fandom drove an artist to the point of attempting suicide over their artwork, in which they drew characters thin that are typically seen as being 'fat' in the show.

[121] In 2018, Kotaku reporter Gita Jackson described the site as a 'joyless black hole', citing how the website's design and functionality led to 'fandoms spinning out of control', as well as an environment that inhibited discussion and discourse.

[124][125] Searching terms like "depression", "anxiety", and "suicide" on Tumblr now brings up a PSA page directing the user to resources like the National Suicide Prevention Lifeline, The Trevor Project, the National Eating Disorders Association, and RAINN, as well as an option to continue to the search results.

[127] In February 2018, BuzzFeed published a report claiming that Tumblr was utilized as a distribution channel for Russian agents to influence American voting habits during the 2016 presidential election.

[129] In May 2020, Tumblr announced that it will remove reblogs of terminated hate speech posts, specifically Nazi and white supremacist content.

[133] In February 2016, the Indonesian government temporarily blocked access to Tumblr within the country because the site hosted pages that carried pornography.

[136][137] Tumblr subsequently removed the ability to disable "Safe Mode" from its Android app,[77] and announced a wider ban on explicit images of sex acts and nudity on the platform with certain limited exceptions.

The user, from New Orleans, Louisiana, had offered to share the human bones reportedly procured from Holt Cemetery by making a post in a Facebook group known as the "Queer Witch Collective".