Inbound email scrutiny and data loss prevention services.
http://www.websense.com/content/email-security-overview.aspx
Email Hosting Providers · Secure Email
Get access to data on 41,520 websites that are Websense Customers. We know of 25,354 live websites using Websense and an additional 16,166 sites that used Websense historically and 8,372 websites in the United States.
Get a list of 41,520 websites using Websense which includes location information, hosting data, contact details, 25,354 currently live websites and an additional 31,077 domains that redirect to sites in this list. 16,166 sites that used this technology previously and 8,372 websites in the United States currently using Websense.