Information-hungry users should be able to focus on the content being provided and not have to think about the mechanical details of transport or representation. Once data is accessible, filtering tools are needed to separate the wheat from the chaff. The job of these tools is to predict how well each particular piece of data would satisfy a user's information need. The relevance decision can also be made automatically. Software-based relevance calculation tools demonstrate the familiar strengths and weaknesses of computers.
Different tools work well with different amounts of data.
If you only have a few megabytes of data to filter, the Unix string-search utility 'grep' does an acceptable job. However, it's usefulness breaks down as the data volume increases. The following table gives an idea of the kind of tools available and the volumes at which they are useful. Once the data has been turned into relevant information, tools are needed to deliver it to the user. These tools include information servers, graphical user interfaces, and gateways to other applications such as email.