MLB Cardinals Manager La Russa files suit over fake Twitter page

What happens when a user creates an account pretending to be a famous athlete, musician or other famous figure and allowing the assumption that the site is authorized by if not created by that personality?  Is there an obligation on Facebook or Twitter to prevent this kind of infringement?  Perhaps the suit filed by Cardinals Manager Tony La Russa last month will bring some clarity to these questions.  ESPN’s report on the story can be viewed here:

http://sports.espn.go.com/mlb/news/story?id=4230602

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