Twitter quietly started checking the URLs that its users post, a security measure aimed at weeding out links to known malware sites.
As online security firm F-Secure points out, the microblogging service “is increasingly targeted by worms, spam and account hijacking” and can easily filter links posted through it.
Twitter hasn’t announced this initiative and didn’t respond to a request for comment about it.
Now, when posting a link to a fraudulent site, it deletes the tweet and flashes the message “Oops! Your tweet contained a URL to a known malware site!”