Edit in JSFiddle

function initialize() {

    var geocoder = new google.maps.Geocoder();
    var myLatlng = new google.maps.LatLng(0, 0);
    var myOptions = {
        zoom: 1,
        //address: 'London, UK'
        center: myLatlng,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };

    var map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);

    //show marker for an address
    function codeAddress(address) {
        geocoder.geocode({
            'address': address
        },

        function (results, status) {
            if (status == google.maps.GeocoderStatus.OK) {
                map.setCenter(results[0].geometry.location);
                map.setZoom(2);
                var infowindow = new google.maps.InfoWindow({
                    content: '<div id="content">Location: ' + address + '</div>'
                });
                
                //var point = results[0].geometry.location;
                //map.panTo(point); // Pan map to that position
                //setTimeout(function(){ map.setZoom(14) },2000); // Zoom in after 1 sec

                var marker = new google.maps.Marker({
                    position: results[0].geometry.location,
                    animation: google.maps.Animation.DROP,
                    map: map,
                    title: 'Hover text',
                    icon: 'http://www.bryantchristie.com/sites/all/themes/bci/img/icon-twitter.png'
                });

                //on click marker, open popup
                google.maps.event.addListener(marker, 'click', function () {
                    infowindow.open(map, marker);
                });
            }
        });
    }


     var searchTerm = 'freekashmir',
        numOfTweets = 100,
        url = 'http://aamirafridi.com/twitter/?q='+searchTerm+'&count='+numOfTweets;
    
    $.get(url, function(data){
        var locations = [];
        $.each(data.statuses, function(){
            if(this.user.location !== "")
                locations.push(this.user.location);
        });
        
        var timer = setInterval(function(){
            if(locations.length === 0) {
                clearTimeout(timer);
                return;
            }
            codeAddress(locations.shift());
        }, 1000);
        
    });
    
}

initialize();
<div id="map_canvas"></div>
html, body {
    height: 100%;
}
#map_canvas {
    height: 100%;
    width: 100%
}

External resources loaded into this fiddle: