Lots of times, when you use APIs they are using Epoc time to specify a date (which is the number of seconds that have elapsed since midnight (UTC),January 1, 1970). This post isn’t to explain why Epoc is that date, though interesting. Here is some quick JS to convert that to a real human date in your local time zone:

function realDate (epoc){
    var d = new Date();
    d.setTime(epoc * 1000);
    return d;
}

realDate(1354908817);
// returns Fri Dec 07 2012 11:33:37 GMT-0800 (PST)