To determine the features and technical requirements that match the needs of your organization, start by identifying your key end-user scenarios. Features and requirements are key, but the user experience is also important, because an unfamiliar, complex, or inconvenient user interface will act as a barrier to adoption.
A successful enterprise search solution gives users an efficient way to access unstructured data, structured information, and expertise. It helps keep sensitive information secure, is easy to set up, administer, and manage, and leaves room for scalability. A successful search solution allows you to customize and extend your search capabilities.
Microsoft Search Server 2008 RTW'ed yesterday, the express edition is free and does the job well!
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