Isolator - What's It All About?
The video below contains no narrative. It does contain music though. "Cissy Strut" by the Meters, if you're interested.
The video demonstrates the Isolator bookmarklet in action, showing how it can isolate distinct sections of web pages. This tool does require mouse use for selection (but the selection can be fine-tuned using arrow keys to move up/down the DOM and left/right to select siblings.
Here's the bookmarklet: Isolator