8. The method of claim 1 , wherein tracking user actions on the email without explicit user feedback using the inserted tracking information comprises: identifying the email with a unique identification before providing the email to the user; and associating the user actions with the unique identification of the email.
1. A method of detecting graymail without explicit user feedback, comprising: receiving a non-spam email for a user; extracting features of the email; passing the extracted features to a classifier model; predicting with the classifier model whether the user would consider the email as graymail; modifying the email by inserting tracking information before delivering the email to the user; storing the inserted tracking information in a tracking database; tracking user actions on the email without explicit user feedback using the inserted tracking information; updating the tracking database upon detection of tracked user actions on the email; determining whether the user considered the email as graymail responsive to the tracked user actions without explicit user feedback; and training the classifier model responsive to the tracked user actions.