Please refre below
https://www-secure.symantec.com/connect/articles/what-protection-does-symantec-dlp-provide-note-beginners
http://www.symantec.com/en/in/data-loss-prevention
https://www-secure.symantec.com/connect/forums/dlp-features
https://www-secure.symantec.com/connect/forums/demo-dlp-video-tutorials-documentation-how-tos
https://www-secure.symantec.com/connect/articles/what-protection-does-symantec-dlp-provide-note-beginners-part-2
https://www-secure.symantec.com/connect/forums/why-i-should-implement-dlp-and-what-its-important-me#comment-8436391