MailChimp is a very successful Web-based email newsletter and mailing list management service. It allows developers to manage multiple large subscription lists, send out newsletters and do it all at low costs and high efficiency.
The FormChimp plugin allows developers to embed a MailChimp newsletter subscription form on their site.
This form includes some cool features like support for AJAX submissions, the ability to subscribe to multiple lists at the same time, and an easy process of integrating it with any MailChimp account.
It also includes customizable error and success messages, and a demo to help any developer get started. Requirements: