One of my clients uses MailChimp for their email marketing. I'm working on rewriting their online ecommerce site in web2py. I figured I'd share this with the community. "pychimp" is a direct port of the official PHP-based MailChimp API. Method names and expected arguments / return values are identical to reduce learning curve.
http://code.google.com/p/pychimp/ Other python implementations can be found on the mc API page: http://apidocs.mailchimp.com/api/downloads/#python If anybody is interested in the web2py module or controller code for this I can post or privately email it. For the most part, when the user registers they may choose to opt in to one of about a half dozen mailing lists. Upon registration an updated JSON message needs to be sent to MailChimp. Furthermore, at any time the user may unsubscribe or change their subscriptions. Note, implementing this requires either changing the form.onvalidate in the user method of the default controller or implementing your own registration / profile. I elected to do the latter.

