Abstract: Agent-mediated commerce method and system, and agents for use therein. Seller agents may offer services at prices that vary over time, based on past experiences. Buyer agents may be configured by their users according to time and constraints, budget and the importance of a specific task. Buyer agents try, probabilistically, to maximize their owners' utilities (in part, by estimating the expected performance of each seller based on the reputation of that seller in the relevant marketplace. Buying agents may reveal only their time constraints and descriptions of the tasks (services) desired to the sellers. Seller agents bid for the offered tasks and base their bids at least partly on their owners' reputations, their time availability, the difficulty of the task and the current demand on the marketplace. Seller reputations are updated in a collaborative fashion based on seller performance. Seller agents employ dynamic pricing mechanisms, including specifically profit maximizing reputation followers.