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The first thing I want to tackle is the past; browsing history. In particular, making some kind of visualization of the "chain" of pages that led you to where you are now.
A pretty easy way to understand this could be a really simple little chain like:
Grizzly Bears - Google search > Grizzly bear - Wikipedia > ...
Another layer of complexity here is the back button, so you can go down multiple routes from one point in the chain:
Grizzly Bears - Google > Grizzly bear - Wikipedia > ...
> Grizzly bear | National Wildlife Federation
> Grizzly bear, facts and photos | National Geographic
The top level of the chain would be whatever the current state of the chain is, alternative routes would be collapsed below it.