Graymail Classification
The graymail engine classifies each graymail into one of the following categories:
* Marketing Email. Advertising messages sent by professional marketing groups, for example, bulletins from Amazon.com with details about their newly launched products.
* Social Network Email. Notification messages from social networks, dating websites, forums, and so on. Examples include alerts from:
* LinkedIn, for jobs that you may be interested in
* CNET forums, when a user responds to your post.
* Bulk Email. Advertising messages sent by unrecognized marketing groups, for example, newsletters from TechTarget, a technology media company.
https://www.cisco.com/c/en/us/td/docs/security/esa/esa11-0/user_guide/b_ESA_Admin_Guide/b_ESA_Admin_Guide_chapter_01101.pdf