I think the point is: If Twitter had remained open, it would have been easy for users to export their graph and take it to competitors with similar features. Tw

I think the point is: If Twitter had remained open, it would have been easy for users to export their graph and take it to competitors with similar features. Twitter closed their friend finder APIs to prevent this. I don't know if App.net could have ever killed Twitter, but Twitter closing made it harder for users to transition to App.net in the first place.