Determining which mail server, groupware, or workflow automation product you need is more complicated than just deciding between Lotus Domino and Microsoft Exchange Server. You need to consider what you want to achieve with your application.
Domino or Exchange Server might be overkill if you run a small business or you need only email services. In this case, your simplest and least expensive option is to use one of the Simple Mail Transfer Protocol (SMTP) or Post Office Protocol 3 (POP3) mail servers available for Windows NT. Examples of these products are Seattle Labs' SLmail, Software.com's InterMail Post.Office, and MetaInfo's Sendmail. (Sendmail implementations are especially attractive if you are already running or migrating from UNIX sendmail.) You can add products that work with SMTP mail servers to provide groupware and workflow support to these basic mail servers. Choosing an SMTP or POP3 mail server gives you the greatest latitude in selecting an email client, because you need only consider support for the Internet standard SMTP or POP3 protocol. These protocols are available in all browser clients, special-purpose email clients such as Qualcomm's Eudora Pro Email, and all current versions of the Microsoft Outlook client. Although Domino and Exchange Server support standard Internet email protocols, this support is secondary to the main product and isn't part of the product's native email protocol.
If you're operating a Novell NetWare 4.x or later environment and using NT as an application server platform, your best choice for an email, groupware, or workflow application is Novell's GroupWise. This product is already integrated with NetWare and Novell Directory Services (NDS) and provides significant advantages in a primarily NetWare environment.
If you haven't decided on an Internet or intranet server platform, you might consider Domino or Exchange Server. Both products offer good Web-server integration. Exchange Server's Web server is Internet Information Server (IIS) 4.0. IIS is free with NT Server and is on the Option Pack CD-ROM. If you use Exchange Server for in-depth application development, you'll find that IIS is a significant component for most tasks. You'll also make extensive use of Active Server Pages (ASP) and scripting languages and tools. You might need to run IIS on a separate machine if your Exchange Server system is heavily loaded. Domino's Web-server component is tightly integrated into the Domino package. Even if you're already running a Web server, you'll also need to use the Domino server. JavaBean development is a key component of the Domino development model.
Exchange Server development uses many skills that your staff might already possess, especially if you are primarily a Microsoft shop. Developing applications for the Lotus Domino or Lotus Notes hierarchical database is a specialized skill, and Domino and Notes programmers are in high demand. The addition of JavaBean support has simplified the task of Domino development.
Exchange Server can use SMTP or POP3, IMAP, and proprietary clients (e.g., MAPI), with good Microsoft Outlook integration. Domino works best with the Notes client. To get the best performance from a Domino server, you must use Notes.
Exchange Server is available for NT, whereas Domino is available for NT, UNIX, and OS/400. This functionality is important in mixed-platform environments.
Domino and Exchange Server offer feature-rich platforms for building your messaging infrastructure. Closely examine each product's features and how they fit into your organization to determine which product most closely suits your needs.