Implicitly agreeing to continue a conversation that may become inappropriate for the regular employer-provided channels.<p>In more archaic terms, he asked for her number so that he could call her up after work.  If she were not at all interested, she would not have released her personal contact info.<p>Obviously, she was not expecting him to <i>immediately</i> blow his chances by making a clumsy, ham-handed, and vulgar come-on.  She [wisely] notified her boss because men that do not demonstrate emotional maturity may have difficulty handling rejection gracefully.