I know very little about this subject, but I was very interested in this Internet News article about the Sarbanes-Oxley act for corporate financial accountability has driven a boom in storage technologies. Companies are trying to comply with guidelines that require not only databases, but unstructured business-related communications such as emails, to be archived.
Emails turn out to be especially problematic, because they're so heterogeneous. To be compliant with Sarbanes-Oxley, you have to store, and quickly retrieve, "all relevant financial records," but at the same time you wouldn't want respond to a request by handing over company communications outside of the focus of the request. Moreover, you'd like to go in to the archives to identify and delete irrelevant emails.
In the end, the article concludes that this up-front pain of developing a compliant archive policy will be beneficial to information-heavy companies. Read the whole thing.