Tumblr has become the target of a chain letter-style spam that spread rapidly over the micro-blogging service.
The fake messages falsely warned that "your blog will be deleted unless you repost this" note, which claimed that Tumblr was drawing up a list of inactive profiles.
Totally untrue, but over 130,000 people were taken in enough to repost the chain spam, according to an assessment of the scam by GFI Software.
Similar scams have been commonplace on Facebook for some time. The Tumblr chain letter took advantage of a shortcoming in the reblog function on the site that meant that more clued-up users could only warn about the scam by reposting the dodgy message themselves.
"The only way users can really warn others is by adding a note to the comments, and the only way to do that is to reblog the original message, thus spreading it further," explained Jovi Umawing, a security researcher at GFI Software. ®