Message Filtering

Even if the system can handle such large amounts of news traffic, how does a poor user sort through it to find information of interest. The solution is to use message filtering techniques to categorize messages according to different criteria. This categorization can be directly used by the user as an awareness feature or automatically by ''agents'' to eliminate certain messages.

We can use several criteria for classifying a message []:

• News Group: The news group to which it belongs, the most common criterion for selecting news messages.

• Discussion Thread: The discussion thread in which it appears, a feature supported by some news clients and also by Notes Mail, which link the messages in a discussion thread.

• Urgent Responses: Whether it is a response to a receiver's message and much time was taken to send the response. Users may be more interested in messages that are part of some urgent conversations in which they are involved.

• Sender/Subject/Contents: Strings appearing in the sender, subject and contents fields of a news item. Certain news clients support ''kill files'' that identify such strings that are not interest to the user such as certain subjects and authors, and these clients automatically eliminate the selected messages. Conversely, others allow users to specify strings selecting messages the user wishes to find.

• Sender effort: How much effort was required by the sender to mail the message: we can distinguish between messages mailed to mass mailing lists and those send individually.

• Moderator selected: Whether some moderator has selected it, a feature supported in moderated news groups.

• Rating: The ratings given by arbitrary users at the local site, as illustrated by the Tapestry system []. This is generalization of the moderator idea, allowing multiple users to pass judgement on a message.