One of the main reasons our partners choose to set up a CiviCRM application is its extended functionality developed specifically for managing all contacts, communications, records and activities of an organization in one place.
Yet one of our clients put a broader meaning into the concept single CiviCRM-based solution and requested new functionality that would allow users to manage their emails (check and read incoming emails, compose new messages, etc.) from the CRM instead of shifting between different applications.