Tumblr was the midwife of radical "Kill All Men" feminism that rose to prominence circa 2010, in the same way that 4chan was instrumental to the spread of right-wing ideologies.

Approximately 25% of female teenage internet users were on Tumblr in 2016. Young adolescent girls would log on to look at pictures of flowers and participate in One Direction fandoms or whatever, only to be met by college-aged Marxist rainbow groomers posting extracts from the SCUM Manifesto ("Society for Cutting Up Men").

Tumblr intentionally cultivated this radical userbase with far-left moderation and overt appeals to the woke. In 2016, they launched Action on Tumblr, "a hub to elevate marginalized voices, educate users on timely political and social issues, and provide resources that can lead to real impact — online and off."

Tumblr declined in 2018 after being forced by Apple to ban porn because child sexual abuse material kept slipping past its filters. The company did little to prevent underage users from viewing porn and many users described Tumblr as a "hellsite of grooming and abuse."

Unfortunately, all of this vital internet history seems to be arcane wisdom on the Right today, but feminist academics and authors often praise the influence of Tumblr:

"the purpose of this paper is to illustrate that Tumblr is ultimately a hopeful space for discussion that has the potential for real social change... although negativity towards feminism is propagated through the anonymity of the internet, Tumblr has become both a location for feminist “world building” as a feminist community of practice. Through this platform comes the reshaping of feminism for the internet generation" (Welcome to the FEMINIST CULT, 2015)

"By the end of the 2010s, reports indicated that the majority of young women identified as feminists – a far cry from the preceding decade marked by ambivalence and unease, if not outright hostility, toward feminism.... Feminism, it seemed, had lost its former reputation as an outdated and dirty word. By 2017, feminism was so central to the zeitgeist that it was declared the Merriam-Webster word of the year." (How Tumblr raised a generation of feminists, 2024)