How to Report on Tumblrby Andrea Ruiz
Socializing on Tumblr is a fairly self-selecting process, since you designate whose content appears on your dashboard by following users' blogs. However, you can't always predict whether a user will post something objectionable, and you may find objectionable content while searching tags, which contain posts from users who may not be on your list of followed blogs. Tumblr enables you to report content that violates its community guidelines through various avenues on the site.
What to Report
You can report any blog or individual post for containing content that violates Tumblr's terms of service. TOS violations include posting content that contains excessive gore or violence, unflagged pornography, malicious bigotry, spam and attempts to impersonate people. You can also report individual users for spam or harassment. Tumblr's Community Guidelines page (link in Resources) contains a detailed list of the types of posts and user behavior that the site considers reportable.
Ignored Users List
If another user is harassing you, Tumblr encourages you to block the user as a first line of defense. You can block the user by either hovering over the username in the post or message and clicking the silhouette button with the downward-pointing arrow, or, in the case of some types of messages, by clicking the "X" button. Once you've ignored the user, you can report the username from within your list of ignored users (link in Resources). Locate the username in the list, and then select either the "Spam" or "Harassment" link next to "Report For" under the username, depending on what you'd like to report the user for. Tumblr sends an instant report to its community managers on your behalf.
If you see a spam post in a tag or on your dashboard, or if an application is posting spam on your own blog, you can report it to Tumblr's staff. Visit the "How to Deal With Spam Posts" page (link in References) and scroll to the bottom of the page, then click the email link and type your report in the pop-up box that appears. You must include the URL to the specific posts, as well as the content and the suspected application in your report.