Ask YC: How do you keep track of the different things you are doing?

I often work in a depth first sort of way. Right now, I am trying to learn Weblocks and get better at Lisp by going through the Weblocks User Manual. But as I read that, I see that it doesn't explain something all that well so I find a separate tutorial for that. As I am reading that, I will see some Lisp concept that I want to read more about, so I open a new tab and read what Practical Common Lisp has to say about it. While reading this I see something else I don't understand so I Google about it, and that leads me to see a quote I like so I open up Emacs to write down some thoughts on it, which makes me realize that I really need a better way to keep track of all the things I am doing, so I write a post on Hacker News about it. In the end, I lose track of all the other threads of thought and learning that I had started.

So my question is - does anything exist that helps with this? Something that just keeps track of the windows and tabs I have opened in a stack-like fashion seems like it would be great - even better if it lets me write notes or keeps track of where I am in each. I know Juice tries to do this a little bit for browsing the web in Firefox but it seems not exactly what I want. Right now I just make notes in a text document but it is distracting to any kind of flow I have going and it seems like a better way should exist.

Thanks!