For example, if you're a registered securities dealer or broker, you probably know you're required to archive the electronic communications of licensed professionals. Another possibility: let's say your company has doubled in staff in less than a year -- you may be reaching the high end of mailbox storage limits and your Exchange server might no longer be at a manageable size. Or if you are a lawyer in a large firm, it may be company policy to save emails that could later be used as evidence in court.

As you can see, email archiving is being driven by a number of areas: compliance, capacity and policy. But which are the factors most important for your organization? And how do you pick a solution that solves the problems without breaking the bank?

Regulatory compliance
Recent press has focused on regulatory compliance for financial institutions, brokers/dealers, and even CEOs -- and the substantial penalties imposed if they don't meet the requirements of long-term storage of email.

SEC Rule 17a-4, for example, requires that all financial institutions retain electronic documents -- including email and instant messaging -- for at least six years. Privacy laws, including Healthcare Insurance Portability and Accountability Act (HIPAA) and Gramm-Leach-Bliley, regulate access to personal information. The Sarbanes-Oxley Act of 2002 creates new disclosure requirements for public companies as well as new certification responsibilities for CEOs and CFOs.

Regulatory compliance usually means saving a copy of every email in a securely indexed format and being able to retrieve messages as and when they're needed. That's vital for some organizations, but it's not the main driver for everyone.

Capacity management
According to The Radicati Group, a market research firm headquartered in Palo Alto, CA, a typical email account sends and receives about 9.6 MB of data per day -- which quickly adds up to 192 GB of data per month for a 1,000-user company. IDC, a global market intelligence and advisory firm in Framingham, MA, predicts that the total number of email messages sent daily is expected to exceed 60 billion worldwide in 2006.

Given the seemingly endless growth of email, the most common reasons to archive are managing mailbox size and making the most of storage. Archiving for capacity management quite simply uses central rules to keep critical data locally and archive off older data to a secondary store. While users can still access their archived data, administrators can more easily back-up and restore the critical stores and offer better email performance. If messages are also compressed, inside or outside the archive, free storage capacity can be increased by more than 50 percent in most cases.