Hi Frank,
On page 38 it talks about using custom fields then making it a hidden field so that when people sign up to your list, preferrably ListMailPro, your affliates put their affilate link into the hidden field. "Make the custom fields "hidden", tell people where to insert their affiliate id's, then ask them to upload your form to their site(s)."
This can be done with ListMailPRO. Basically your HTML page should be able to process PHP, which can be achieved in .html files if necessary via an .htaccess file:
RemoveHandler .html .htm
AddType application/x-httpd-php .php .htm .html
Next, instruct your affiliates to browse to a particular URL, ie:
http://example.com/subscribe.html?r=affiliateID
In a ListMail signup form in subscribe.html pass the "r" variable via a hidden custom field and embedded PHP:
<input type=hidden name=user1 value="<?php echo $_GET['r']; ?>
">
You should only need one custom field to store the referrer of each user. A simple custom MySQL query run in a program like PhpMyAdmin could list top referrers by counting the users they have referred:
SELECT user1, count(*) AS referred FROM lm_users WHERE list = '1' GROUP BY user1 ORDER BY referred DESC
Please let me know if you have further questions on this :D
Regards