While every virtual world has developed in world methods of communications, the problem of establishing communications between a person in one virtual world with another person in a completely different virtual world has not been solved. Virtual worlds provide an environment for rich communications not previously available thru avatar animation. Virtual worlds also provide a common environment for mixed modes of communications such as text and voice in addition to the gestures and emotional indicators presented thru avatar animation. Virtual worlds also provide private or public communications to occur between individuals or groups. The problem here is how to extend this beyond the confines of a single virtual world.
1.4 Media streaming
Each owner of the virtual world needs to be able to specify what and what can not be done in their world. In a large world this may be subdivided down to account holders. Policies determine the rules of engagement between avatars and their environment. While this may be determined completely from the server side, we need to look at what needs to be done from the client point of view as well. Do we tell the client what it can do and what it can't do or do we just ignore requests from the client that is not allowed.
Along with defining policies as a capability of virtual worlds, we should also look at basic rights for visiting avatars. When we move from world to world, we must retain rights to control our avatars. We can not allow impersonation or hijacking of our avatars. We must always be allowed to leave a virtual world.
2.1 Avatar rights
2.2 World policies
3 Global presence
The are of global presence covers areas that are independent of the virtual worlds and answers questions such as if my friend online and if so where? Global presence is a manner of finding contacts beyond IM, telephone network and virtual world presence. We want to be able to locate our friends and associates no matter what service or virtual world they are connected to (with their permission of course). A global presence system will allow a user to move from one system to another without entering login information again and again. When someone wishes to find someone online, the global presence system will connect them to the desired party no matter how or where they are connected.
The global presence system provides a central authority for identity of users. Pseudo - identities are allowed and protected as one moves from one virtual world to another. A users real identity is always protected as securely as possible.
When a user enters a new virtual world, the global presence system logs them and identifies to the virtual world the avatar and pseudo - identity that is to be used.
When a user wishes to contact someone, the global presence system figures out how to connect the two parties without revealing either one's location to the other.
Content is the most significant aspect of interoperability between virtual worlds. The issues surrounding the moving of avatars and other content between virtual worlds is the most challenging and will require the most effort.
The first thing we must realize is that avatar content can come from anywhere on the web. Just as images and other forms of content are distributed across the web, we need a way to allow people to own their own content and save it where they wish. In order to do this we need to provide a method of locating content similar to the way URLs are used today.
The specification of 3D content and more abstract content such as agents or presence may require more than just URL to well defined class of object such as an image or html page. Context will be important in determining the proper content that is sent to the requesting party. Context will include such factor as user preferences, owner defined properties, viewer capabilities and environmental variable on a global scale. In the future what each person experiences as they browse the 3D web will be different based on their user profiles. These profiles will be generated with or without the users knowledge.
We need to look at what type of content we want to support as we move from one world to another. 3D content is a given of course, but there are more complex data types we need to consider. The avatar itself is much more than a 3D object. It is an animatable object. It is tied to communications channels. It is also scripted. A major focus needs to be placed on how to move avatars between worlds of which 3D objects is only a small part of the problem.