Information goods/services, like those provided in the UMDL, are very hard to compartmentalize into equivalence classes that all agents can agree on, especially if the agents are software agents who are constantly changing their preferences in order to maximize their profits. For example, if an encyclopedia database access is defined as a good, then all agents providing encyclopedia accesses can be considered as selling the same good. It is likely, however, that a buyer of this good might decide that seller s1 provides better answers than seller s2. We cannot possibly hope to enumerate the set of reasons an agent might have for preferring one set of answers over another, and we should not try to do so. It should be up to the individual buyers to decide what items belong to the same good category, each buyer clustering items in, possibly, different ways.
This situation is even more evident when we consider an information economy rooted in some information delivery infrastructure (e.g. the Internet). There are two main characteristics that set this economy apart from a traditional economy.
If these two characteristics are present in an economy, it is useless to talk about supply and demand, since supply is practically infinite for any particular good and available everywhere. The only way agents can survive in such an economy is by providing value-added services that are tailored to meet their customers' needs. Each provider will try to differentiate his goods from everyone else's while each buyer will try to find those suppliers that best meet her value function.