"filters":
    {
        "states":["read"],
        "respondents" : ["userID"],
        "answeredQuestions" : [
            {
                "question":"Question Value",
                "answer":"answer value"
            }
        ],
        "surveysTaken" : [ ],
        "facebookUserData":{
            "gender":"male"
        }
    }

If you want to send the message or the survey to all your subscribers, just delete the respondents form this object, or put the variable to null.