Twitter has fixed a major bug that saw many users of the service appear to lose all of their followers and friends. The problem began when a flaw was uncovered that allowed people to force others to "follow" them on the site.
People who typed "accept" followed by a person's Twitter name forced the user to be added to their list of followers.
The hack was quickly passed around the social network with many people using it to force celebrities to follow them.
It could have easily allowed spammers to insert messages into thousands of accounts.
Twitter quickly closed the loophole but was forced to temporarily reset many accounts as it cleaned up the damage. The reset made it look like many users had no followers and were also following no one.
"We identified and resolved a bug that permitted a user to 'force"' other users to follow them," the site said in a blog post.
People were still able to use the service during the disruption.
Twitter allows users to post messages - known as tweets - up to 140 characters long.
People can see what others are writing by choosing to "follow" them. However, unlike many social networks, both parties do not have to reciprocate the friendship.
The new bug allowed many people to force celebrities, such as Lady Gaga, to follow them by simply typing "accept @ladygaga".
This would make it appear that Lady Gaga had chosen to follow them and would also inject a user's tweets into the singer's feeds.
The flaw only worked on the website and not through third-party software used to access the service, such as Tweetdeck.
Twitter has exploded in popularity since 2007, when it was launched, and now has more than 100 million users.
News of the flaw follows the discovery of a recent high-profile security bug at Facebook, another poster child of the social web.
The exploit - now fixed - exploited the site's privacy settings and allowed users to eavesdrop on their friends' live chats and see their pending friend requests.
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