I use different browsers to logically separate my groups of viewing habits. One is open for casual HN style surfing, one for a hobby I'm work on, one for work, one for school, one to isolate media apps like Pandora or Hulu, etc. Each has a queue of pages I was working on/reading/in the middle of something and had to run out to a meeting or whatever and didn't get back to it immediately. Heck I've had half-written replies in emails up for days in a separate browser with all of the related research tabs I was using while constructing the email up as well.

I tried to keeping myself to just a handful of tabs in a single window but I found I was missing so much good stuff I just gave it up.

I find this only works if you have a high abstract -> concrete learning style (sometimes called "synthesizers"). Not everybody works that way and that's fine - but other workflows drive me batty. Once I've assembled everything in a browser instance, I can even let it go for a week or two, forgetting completely about it before returning devoting my attention to the "concept" of that instance -- the semantics of what it's for are all there because everything is grouped in an instance. I can dash off a several thousand word paper in just a few hours of focused concentration because all of the research is done and sitting there for me -- left by my past self.

But if, like most people, my attention wanders after a few hours, I can switch instances and immediately context shift to a completely different semantic set and let my mind chew on the other problem unconsciously.

Even IRL, when in college, I'd have different tables setup the same way for different classes or projects. All the books and research notes in a stack next to the half-written paper.