The Campaigner Python SDK by João Magalhães communicates with the API to access email marketing campaign features. Controllers and models are available as resources, in addition to initialization in Python language.
Additional third party integration with Gmail has been possible (you only have to look at all the contact import features from sites like Facebook), but these have either been clunky manual procedures that involve exporting contacts to a CVS file, or they require you to supply your email password. Neither option is all that attractive. Now there is an alternative. Google have recently added the ability to access the IMAP/SMTP features of particular Gmail account using OAuth.
The focus of Gravity Rock Solid Recommendations is to help its business clients offer personalized recommendations to their customers. Their clients funnel lots of content, like video streaming sites, dating sites, Groupon imitators, classified sites and ad networks to consumers. The Gravity R&D API uses events to track user interactions. From there they import an item catalog to build user profiles to create the individualized recommendations.