Protecting Servicemembers Online Act of 2017 This bill subjects to a court-martial under the Uniform Code of Military Justice a person who: knowingly broadcasts or distributes an identifiable visual image of another person who is at least 18 years old, who is engaged in a sexual act or exposes a private area, and who had a reasonable expectation of privacy in the depicted conduct; knows that the image was to remain private; knows that the depicted person has not consented to the broadcast or distribution; and broadcasts or distributes the image with the intent to harm, harass, intimidate, or coerce such person. The broadcast or distribution by a person of his or her visual image to one other particular person shall not by itself constitute consent for such image's broadcast or distribution by that particular person to any other person. The bill also subjects to a court-martial a person who: intentionally engages in a course of conduct with the intent to cause harm through directing harassing communications at another specific person; and causes harm to such person or to such person's military unit by such communication.