Abstract: Techniques are described for providing and managing interactive communication sessions between client computing devices, such as via Web browser software executing on the client computing devices to interact with server computer devices providing a shared visual interaction environment for the devices, and with the shared visual interaction environment being dynamically customizable to add and/or remove selected types of functionality that have corresponding visual representations in the shared visual interaction environment. In some situations, the described techniques include providing multiple predefined types of functionality and/or enabling users to add new types of user-defined functionality, using visible layers that each present one or more types of visual information or other visual effects corresponding to at least one of the functionality types.

Abstract: Techniques are described for providing and managing interactive communication sessions between client computing devices, such as via Web browser software executing on the client computing devices to interact with server computer devices providing a shared visual interaction environment for the devices, and with the shared visual interaction environment being dynamically customizable to add and/or remove selected types of functionality that have corresponding visual representations in the shared visual interaction environment. In some situations, the described techniques include providing multiple predefined types of functionality and/or enabling users to add new types of user-defined functionality, using visible layers that each present one or more types of visual information or other visual effects corresponding to at least one of the functionality types.

Abstract: Methods and apparatus support optional user authentication. Whether an authentication, or an enhanced type of authentication, is required before proceeding with a transaction can be determined on a user-by-user basis. Some credit card users subscribe to a service that provides the users with security tokens. Transactions involving these credit cards may require correct entry of a security token code, before the transactions are allowed to proceed. However, other credit card users, i.e., users who have not subscribed to the service, are not required to enter a security token code before their transactions are allowed to proceed.