with console.logs

updated?

var YOUR_API_KEY = ''
var dateUpdated = "";
 
function changeTitle() {
    var favi = jQuery('[rel="shortcut icon"]');
    var titleDate = jQuery('p.author a').last().attr('title');
    var reDate = /(\d+)\/(\d+)\/(\d+)/;
 
    //Swap year and day, convert to Date obj
    titleDate = (titleDate).replace(reDate, "$3/$2/$1");
    titleDate = new Date(Date.parse(titleDate))
 
    jQuery.get(
        location.pathname + '.json',
        {key: YOUR_API_KEY},
        function(data){
            dateUpdated = data.issue.updated_on;
            dateUpdated = new Date(Date.parse(dateUpdated));
            console.log(dateUpdated.getTime(), dateUpdated);
            console.log(titleDate.getTime(), titleDate);
            console.log('------------------------------------------------');
            if (dateUpdated.getTime() > titleDate.getTime()) {
                setTimeout(changeTitle, 3000);
                favi.attr('href', 'http://cdn.dustball.com/time_add.png');
            }
        }
    );
}
 
changeTitle()