This is a really quick and dirty sample application showing how a possible web-based object system might work for developing online multiplayer games. Apologies if there are bugs in this, I put it together pretty swiftly.
The right hand column lists all the Object Templates that are in the database. An Object Template would provide the basis for any object in the game, and each object in the game would be based on one template. The template defines fixed attributes about the object, such as name, mass, or whether it is a container. Actual objects in the game will be instances of a template, so they could contain properties that are specific to that instance, such as hit points, magic points or anything else variable.
The left hand column shows all the possible interactions in the database. An basic interaction consists an exchange between one or more input objects to one or more output objects. For example, Striking a match: the player starts with a matchbox and a match ( the inputs ), after performing the interaction the objects remaining are the same matchbox and a lit match (the outputs).
The idea would be that any game creators out there could add objects and interactions to the database. We would build up a large database of objects with many different interactions between them. Objects and Interactions would have to classified in many different ways ( time-period, style, etc... ) and game creators could pick and choose the objects and interactions that they want to use in their game. That way all game creators benefit from a vast array of prefab objects with interactions, but they can customise the object list they their game uses.
I think this system would be particularly well-suited to Monkey Island type adventure games where you are often combining objects but I see no reason why it wouldn't work with a more traditional RPG too. As long as there was a suitable property system so that each instance could have it's own values.
The classification and selection tools and system for game creators would be very important, as there could potentially be thousands of objects and interactions.
The Object System would be provided as a web-service with a REST-like interface that online games could access.