In the last 24 hours Tumblr users have been reporting that their pages have been hacked, with them unable to delete unwanted content.
Pornographic material, random posts and random messages are reportedly appearing on the pages, with the blog owners saying they weren't responsible for the posts.
The Threat Track Security blog claims that over 800 users have been affected, with many complaining about it on Twitter.
What went wrong
We've now spoken to Tumblr who told us: "Earlier this morning, an infrastructure failure lasting roughly fifteen minutes led posts created in this window to become corrupt. No data was lost, but this has been causing inconsistent behavior for these affected blogs. Our engineering team is working quickly to correct the situation."