This example Java applet, from C-Net, is an excellent demonstration.

You interactively move the sliders to indicate you preferences - how you value performance, ergonomics, etc. Then you press Submit, and the applet queries a server with information on hundreds of PCs. The result is a selection of a few choices, plotted by price and “value”, as defined by your preferences.

You can the click the dots on the plot and get more information on each machine.

The applet is highly interactive, with hot pop-up zones and a cursor-sensitive help box at the top right. This typ of computation is not realistic to do remotely, and it is here that Java excels.