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 36,532 websites that are Websense Customers. We know of 22,310 live websites using Websense and an additional 14,222 sites that used Websense historically and 7,230 websites in the United States.
Get a list of 36,532 websites using Websense which includes location information, hosting data, contact details, 22,310 currently live websites and 14,222 sites that used this technology previously and 7,230 websites in the United States currently using Websense.