Streams is a keyboard friendly way to write and easily divide your text into separate tiddlers while writing. Every time you want a new tiddler, just hit Enter. A new tiddler is created in the background and you can just continue writing.
The widget subclassing mechanism allows widgets to be subclassed with additional methods and properties. The subclassed widgets can either overwrite the existing definition of the baseclass widget, or it can be made available as a new widget