Because malicious applet source code has been put on the Web, hundreds of people can start to use and adapt the ideas. We have been lucky that this has not happened yet. Perhaps we will continue to be lucky, or perhaps not. As we have seen, an applet need not break into your machine in order to do malicious things. Sometimes it is good enough to steal CPU cycles, or deny access to other sites.
Malicious applets come in all shapes and sizes.
Defending against all of the possibilities is at best a daunting task. Malicious applets may even play a role in undermining business on the Net. Recall the Business Assassin applet that targets Gamelan. Another malicious applet could spam the Net with ads supposedly from you, should you be from the site of a competitor. This could effectively cut your business off the Net when people respond with mail bombs.