1. A method comprising: receiving, at a virtual machine associated with a particular user, a notification from a mobile device associated with the particular user identifying that a message received at the mobile device is determined to be an unwanted message based on: identification of the message as a potential unwanted message by an unwanted message detection algorithm; and the message being confirmed by the particular user to be an unwanted message; updating, at the virtual machine, a copy of the unwanted message detection algorithm associated with the particular user, based on the notification to generate an updated unwanted message detection algorithm; transmitting the updated unwanted message detection algorithm to the mobile device associated with the particular user.