You will have to hack the user.module for this. So be careful while you upgrade.
Find this place at around line 570 in user.module (in function user_block):
<?php
case 2:
if (user_access('access content')) {
// Retrieve a list of new users who have subsequently accessed the site successfully.
$result = db_query_range('SELECT uid, name FROM {users} WHERE status != 0 AND access != 0 ORDER BY created DESC', 0, 5);
while ($account = db_fetch_object($result)) {
$items[] = $account;
}
$output = theme('user_list', $items);
$block['subject'] = t('Who\'s new');
$block['content'] = $output;
}
return $block;
?>
And change these three lines:
<?php
$result = db_query_range('SELECT uid, name FROM {users} WHERE status != 0 AND access != 0 ORDER BY created DESC', 0, 5);
//Change to grab the created variable which stores the user's creation timestamp:
$result = db_query_range('SELECT uid, name, created FROM {users} WHERE status != 0 AND access != 0 ORDER BY created DESC', 0, 5);
?>
<?php
$items[] = $account;
//Change to make each $items be a link to the user's profile page with the timestamp formatted:
$items[] = l($account->name . date(" n-d-y", $account->created), "/user/$account->uid");
?>
<?php
$output = theme('user_list', $items);
//Change to output an item list instead of a user list (which is really an item list that makes the same links we just made above based on a name/uid array:
$output = theme('item_list', $items);
?>
Contributed by rszrama http://drupal.org/user/49344
