I found the article, Linux answers some messaging challenges, to be very good and will look at evaluating the uses on antispam and antivirus methods on a Linux platform. What are some applications that could be used with Linux to support calendaring, tasks, and other things besides just e-mail?
There are a number of Linux products that address e-mail, calendar and task functionality. These include IBM Lotus Notes/Domino, Novell GroupWise and Oracle Collaboration Suite and the Scalix Email and Calendaring Platform. You can find more applications in various online application catalogs such as the Red Hat Solutions catalog and in online application catalogs such as Knowledgestorm.
This was first published in May 2004