How do you interpret "Last Active" in Admin

When I log into the admin panel I see a list of all "Registered Members" and one column has last active.

I know this number increases everytime a member logs in, but is there a way to interpret it. Does it represent the date and time for instance. As an example,

This is my Last Active:

1369408196 (When I logged in on 5/24/2013 at 11:10am EST)

Logged out then logged back in and my number was this.

1369408310 (5/24/2013 at 11:11am EST)

Any help would be appreciated.

Add this at the very bottom of "include/session.php"

Code:

function Agotime($date)
{
    if(empty($date)) {
        return "No date provided";
    }
 
    $periods        = array("second", "minute", "hour", "day", "week", "month", "year", "decade");
    $lengths        = array("60","60","24","7","4.35","12","10");
 
    $now            = time();
    $unix_date        = strtotime($date);
 
      // check validity of date
    if(empty($unix_date)) {   
        return "Bad date";
    }
 
    // is it future date or past date
    if($now > $unix_date) {   
        $difference    = $now - $unix_date;
        $tense        = "ago";
 
    } else {
        $difference    = $unix_date - $now;
        $tense        = "from now";
    }
 
    for($j = 0; $difference >= $lengths[$j] && $j < count($lengths)-1; $j++) {
        $difference /= $lengths[$j];
    }
 
    $difference = round($difference);
 
    if($difference != 1) {
        $periods[$j].= "s";
    }
 
    return "$difference $periods[$j] {$tense}";
}    

And add this to user info

Code:

/* Last active */
$today = getdate($req_user_info['timestamp']);
$ax = $today['month'] . " " . $today['mday'] . ", " . $today['year'];
$ax .= " " . $today['hours'] . ":" . $today['minutes'] . ":" . $today['seconds'];

echo "<tr><td><b>Last Active:</b> </td><td>".Agotime($ax)."</td></tr>";