Applet Channel
Defining an Applet channel is actually very easy. Applets, as you know, are very powerful. They provide a distribution solution by requiring browsers to pull them, and their support libraries, from a server. The user interface that may be presented to a user is much more feature rich than is available through the use of standard browsers and HTML.
The decision to place Applets at the top of the difficulty scale is based largely on their absence in the industry. Conceptually applets are a savior; in reality they never met their objectives. Some have been very successful at Applet deployment, for others, horror stories abound. Success or failure, deployment of applets requires an effort on the scale of distributed systems where one component is a desktop application requiring human interaction. The complexity of such an implementation clearly pushed Applets to the far end of the difficulty scale.