This paper presents the design and implementation of an Event-Trigger-Rule-Based auction system called IntelliBid. A network of Knowledge Web Servers, each consisting of a Web server, an Event-Trigger-Rule (ETR) Server, an Event Engine, a Knowledge Profile Manager, and Bid Servers and their proxies constitutes IntelliBid. Together, they provide auction-related services to the creator of an auction site and the bidders and suppliers of products. IntelliBid offers a number of desirable features. First and foremost is the flexibility offered to bidders for defining their own rules to control their bids in an automatic bidding process, which frees the bidders from having to be on-line to place bids. By using different rules, the bidders can apply different bidding strategies. Second, it furnishes valuable statistical information about past auctions to both suppliers (or sellers) and bidders. The information can assist a bidder in bidding and a seller in setting a reasonable base price and/or the minimum incremental price. Third, since rules that control the automatic bidding are installed and processed by the ETR servers installed at bidders' individual sites, bidders' privacy and security are safeguarded. The statistical information that is released by IntelliBid only depicts the trend of the bidding prices of a product. The information about bidders is kept completely secret, thus safeguarding the privacy of the bidders. Fourth, IntelliBid's event, event filtering and event notification mechanisms keep both bidders and suppliers timely informed of auction events so that they or their software system can take the proper actions in the auction process. Fifth, any registered user of IntelliBid, bidder or supplier, can monitor the bids placed to any product being auctioned in IntelliBid. Sixth, IntelliBid allows bidders to do both on-line (or manual) bidding and automatic bidding. It also allows a bidder to participate in several auctions at the same time, in both manual and automated modes. The bidding of a product can depend on the result of the bidding of another product. Last, but not least, IntelliBid allows a person or organization to play both the role of bidder and the role of supplier simultaneously. The Profile Manager keeps the information as a bidder and information as a supplier separately. Moreover, IntelliBid's architecture uses a parallel event management system to do event registration and notification. This paper also reports the result of a performance study on the implication of using such a parallel system to achieve scalability.