Creating filters to do this automatically. Eudora has a very capable set of filtering tools to assist with management of e-mail messages. It can examine messages, incoming and outgoing, for matches to rules. Common techniques involve looking for a certain string of text in a header or the body of the message. For example, any message to or from a certain person, or with a certain word or phrase in the subject line would be placed in a certain mailbox.
Filters can have a number of actions defined.
An obvious action is transfer. This places the message into a mailbox. Others include printing the message, playing a certain sound, forwarding the message to someone else, etc. Visiting a web site using a URL in an e-mail message. If there is a URL in the text of a message, Eudora will usually identify it and make it an active link.