def do_not_track(request):
    """
    Detect the "Do Not Track" HTTP header: http://donottrack.us
    """
    dnt = request.META.get("HTTP_DNT", None)
    # if dnt is "1", the user does not wish to be tracked
    # if dnt is "0", the user explicitly consents to be tracked
    # if dnt is not set, the user hasn't stated a preference
    return {
        "DO_NOT_TRACK": dnt == "1"
    }