More recently electronic agents have emerged as a way to customize searches to automatically lead consumers to a shorter, richer list of information of particular relevance and importance to them. The electronic agent watches the session, discovers what types of information and products the user may be interested in, and then stores this information for future use. However, the way that they accomplish this and the degree to which they add intelligence vary greatly. Anchored agents do most of their work on either the client side or on the server side. Examples of client side agent are E-mail packages on a PC, like Eudora or MS Exchange, which sort incoming messages into separate mailboxes by specified parameters such as name of sender or subject words.
Anchored agents are the most common type in existence today.
Mobile agents make up the more sophisticated group and have the most promise, although they have not yet been implemented with great success. These agents are self-contained executing programs that move themselves from server to server to find what they need. Today, it's natural to think of programs grabbing resources from remote spots on the Web, but to have a program jump to another server and execute is just beginning to happen. Some of the benefits of mobile agents include reducing network traffic, minimizing the effects of network outages, and distributing computational workload to various machines. The second primary dimension of Internet agents relates to the intelligence and level of autonomy that an agent has.