Well, the obvious costs are storage capacity and backup capacity; you keep growing, you keep adding storage. But, searches of existing files can cost quite a bit too. For example, if we look at Internet searches that we do every day, we're basically searching through unstructured data using simple search criteria, such as text strings. I mention this because the mechanisms used to search unstructured data are very similar.
A 2003 study claimed that office workers spent five and a half hours per week searching the Internet for information. That's about 14% of your workweek spent looking for data. You can see how the cost really adds up. Imagine a legal dispute where you need to produce information for discovery. You can spend significant time looking for specific email messages or other data, so search costs can become enormous.
Listen to the Unstructured data FAQ audiocast.
Go to the beginning of the Unstructured Data FAQ Guide.