In the first of the Vitual Observatory (VO) sessions François Ochsenbein talked about Aladin, the CDS killer application.
Aladin development started 7 to 8 years ago and has evolved into a tool which includes a number of services, fufilling the need to put astronomical data onto the astronomer's desktop. The goals of Aladin development is interactiveity, performance, ease of installation and connectivity.
Aladin in written in Java and one of the strengths of Java is the ease of interactivity, but it has notoriously slow. Aladin has always pushed the limits of Java performance as it has improved (e.g. JIT compiling). However it also provides good ease of installation, although the applet concept is now dying.
The real power of Aladin is in it's connectivity to a large range of different data sources, and it's ability to interoperate with other Java applications like VOPlot and VOSpec.
The next step is to extend Aladin to access the emerging web service infrastructure.