Access to the Web is becoming ubiquitous. Creating basic Web pages is very cheap. Multimedia can be supported, to an extent. Long movies at high resolution are too big to send over the Web, for example. But short clips work great.
Interaction is supported, but limited.
You're not going to move sliders around and see dynamic simulations on basic WWW pages. Java Java is a language that can be used to create small, downloadable applications over the Web. Relative platform independence. But the big win is interactivity. Java can support really neat interactivity.