I want to learn some more about sessions. Currently, I know next to nothing. This is in the manual:

PHP Code:
<?php
session_start();

if (!isset($_SESSION['count'])) {
    $_SESSION['count'] = 0;
} else {
    $_SESSION['count']++;
}

echo $_SESSION['count'];
?>
Which counts how many times a user has viewed a page. But I want to learn what cpradio is working with. Counting the number of users on a page. Does anyone have any info that could help me?

What's the life of a session, also? When do they expire?