1. A method for interactive content retrieval and display at a computer connected to a network and having Internet access, the method comprising: providing a plurality of portlets selected by a user from a plurality of sources available via the Internet for retrieval of content for display in a user interface; in response to user input at the computer, defining a particular message action to be taken in response to user interaction with a first portlet, mapping the particular message action to a first portlet to create a messaging portlet for sending a message to a registrar in response to user interaction with the messaging portlet; wherein said registrar is located in a browser at the computer; creating a listener portlet by registering a second portlet selected by the user with the registrar to receive messages from the messaging portlet; in response to user interaction with the messaging portlet, retrieving particular content for display in the user interface based on the message received by the listener portlet from the messaging portlet; and displaying the particular content in the user interface.