Twitter has scrambled to close a programming loophole that allowed users to add any other site member as a follower without their permission.
The company said it had fixed the bug that had permitted a user to “force” other users to follow them.
It had to temporarily reset all followers and following numbers while the bug was closed.
The loophole, discovered by a Turkish user and publicised by Gizmodo writer John Herrman, let users add any user as a follower with only two words - accept <username> - via the main Twitter web interface.
Herrman said he had used the bug to force US talk show host Oprah Winfrey to follow his Twitter feed.
The intended function of the accept command was to provide people with protected twitter accounts the option of accepting follow requests via console commands.
But it is surprising that a command with such wide-reaching applications had lain unpatched – and unnoticed – for so long.