Without realising it, your Drupal site is losing customers / subscribers because they can't log in. A surprising proportion of people fail to understand that the user login form provides a request password facility. To overcome this, we have written "Forgotten Login", which monitors and reacts to failed logins.
It is designed to help users of your site who have attempted and failed to login X number of times, after which a customizable e-mail is automatically sent to the user with the Drupal one time login URL so they can login and reset their password.
This module is valuable for any ecommerce, ubercart or membership based website where users are valuable. It emits the fact that you care about your users.