Facebook, MySpace and Google signed a pact with the European Union on Tuesday to improve safeguards against the bullying and abuse of teenagers online. The EU said networking sites are currently used by some 42 million people in the bloc and warned that youngsters need to be protected from abusive behavior. The agreement signed by 17 site operators in the EU commits them to limit the risks of misuse by providing a “report abuse” button. This allows users to report “inappropriate contact from or conduct by” another user to the site operator.