SQL Server 2005 Server-Level Fixed Roles
SQL Server 2005 Server-Level Fixed Roles
Fixed server roles are server-wide in their scope. Each member of a fixed server role can add other logins to that same role
The fixed server roles are:
* bulkadmin
* dbcreator
* diskadmin
* processadmin
* securityadmin
aiDeeva.com 
Why the Center for Internet Security recommends to avoid assigning these roles to application database user accounts, application administrator accounts, application developer accounts or application roles?