Google Spam Filter. In this post MailChimp provides terrific insights that they have gained after sending more than 4.6 Billion emails to Gmail customers this year.

Email-Marketing

The post also covers Gmail’s new Unsubscribe Link and Feedback Loop check it out at http://blog.mailchimp.com/gmails-new-unsubscribe-link-and-feedback-loop/

and of course if you need any help with your email marketing let me know.