Web Content Monitoring - 2nd post

[Deshwal Chand <CDD () kampsax co in>]

HI 
We are company working in the field of GIS, a very high security data zone.
We have signed the condentiality agreements with the clients.
We intend to monitor the web contents, specially the e-mails, which are sent
by them using Yahoo or Hotmail etc accounts. The intention is not to snoop
on the users.
I want to get alerts on specific keywords being used in the traffic going
out of the network. 
Is it possible using snort. 
BR
Chand