Back in September I wrote a blog post titled "Tumblr Is Begging Users: Please Stop Asking for Porn". Less than two months later they've loosened the regulations a little bit -- porn is still a no-no, but you can go ahead and post your nude pics again.
A post explaining the change said:
“We now welcome a broader range of expression, creativity, and art on Tumblr, including content depicting the human form (yes, that includes the naked human form). So, even if your creations contain nudity, mature subject matter, or sexual themes, you can now share them on Tumblr using the appropriate Community Label... We still don’t allow hate, spam, violent threats, or anything illegal, and visual depictions of sexually explicit acts remain off-limits on Tumblr."
Things started going downhill for Tumblr when Yahoo! bought the platform in 2013 and immediately banned all sexual content. This change could bring some users and advertisers back.