The microblogging site has blocked #gay, #lesbian, and #bisexual on searches in iOS app.
Micro-blogging and social networking site Tumblr has banned some porn-related search tags on its mobile apps in a bid to comply with the requirements of particular app environments.
The micro-blogging site has been blocking searches for #bisexual and #lesbian on iOS platforms, while reports suggest users are still able to view unfiltered search results on the site.
Tumblr chief executive David Karp said that tags like #gay were allowing adult material through, which meant the app was nearing being banned in some stores and site administrators were reluctant to begin classifying certain blogs as ‘adult’.
"We’ve taken a pretty hard line on freedom of speech, supporting our users’ creation, whatever that looks like, and that’s just not something we want to police," Karp said.
Users have been complaining over the issue and they have also filed more than one online petition.
Tumblr has also blocked tags on particular apps, including the version used on Apple’s iOS software, while users are still able to view unfiltered search results on tumblr.com, even on their mobile web browser.
The app also allows users to browse the moderated tag #lgbtq, which is an acronym for lesbian, gay, bisexual, transgender/transsexual and queer.
Acquired by Yahoo in May for $1.1bn, Tumblr also allows the sharing of explicit pictures providing they are labelled not safe for work [NSFW].
"There haven’t been any recent changes to Tumblr’s treatment of NSFW content, and our view on the topic hasn’t changed," Karp added.
"Empowering your creative expression is the most important thing in the world to us. Making sure people aren’t surprised by content they find offensive is also incredibly important and we are always working to put more control in your hands."