https://www.reuters.com/article/us-facebook-privacy-zuckerberg/long-lines-protest-before-facebook-ceo-zuckerberg-testifies-idUSKBN1HH1CU >Facebook Inc Chief Executive Mark Zuckerberg will strike a conciliatory tone on Tuesday in testimony before Congress as he looks to fend off the possibility of new regulations as a result of the privacy scandal engulfing his social network.