Originally Posted by Itchy

Unflagged NSFW Blogs. Tumblr is home to millions of readers and bloggers from a variety of locations, cultures, and backgrounds with different points of view concerning adult-oriented content. If you regularly post sexual or adult-oriented content, respect the choices of people in our community who would rather not see such content by flagging your blog (which you can do from the Settings page of each blog) as Not Suitable for Work ("NSFW"). This action does not prevent you and your readers from using any of Tumblr's social features, but rather allows Tumblr users who don't want to see NSFW content to avoid seeing it.