Defence against the effects of the Epsilon Security breach
The biggest mass emailer in the world, Epsilon, recently suffered a security breach as outlined in this press release: http://www.epsilon.com/News%20&%20Events/Press_Releases_2011/Epsilon_Notifies_Clients_of_Unauthorized_Entry_into_Email_System/p1057-l3 .
This carries some dangers of spam being sent to these stolen email addresses, spoofing the legitimate customers of Epsilon. There is an easy defence against this: DKIM. Symantec Messaging Gateway supports DKIM filtering and allows to defend against spoofing attacks based on Epsilon's security breach.