The message would be visible if you set your guestbook as shoutbox, otherwise, hidden i've written a topic on how to use guestbook as shoutbox HERE...
TIPS
*Create a new user ID or use an existing user ID
*Simply edit incfiles/head.php and put this at the last line
mysql_query("UPDATE `users` SET $sql `total_on_site` = '$totalonsite', `lastdate` = " . time() . " WHERE `id` = '706'");
*change 706 to the bot ID
To make Bot post in shoutbox after registration
,
Open registration.php
locate this code
<?php
$usid = mysql_insert_id();
?>
Then insert this code above it.
$time = time();
$bot = 'Hi @'.$reg_nick.', welcome to MobileLoaded! ';
mysql_query("INSERT INTO `guest` SET
`adm` = '0',
`time` = '$time',
`user_id` = '706',
`name` = 'MobileLoaded',
`text` = '" . mysql_real_escape_string($bot) . "',
`ip` = '0000',
`browser` = 'iPhone 4S/Mobileloaded '
");
DEMO HERE