Clive Thompson has a great rumination on a missing piece of the Internet toolsuite: a mapper that watches your browsing and tells you how you found interesting stuff. This is a great example of a technology that would make a wonderful local add-on to your browser, but would be creepy and invasive if offered as a centralized server. That is, it'd be great to know this stuff yourself, and great to have the option to share it with others, but it would be pretty icky to think that some remote, behavioral-ad-analytics-driven entity was using it to build a dossier on your Internet use.
But later on, it's damn hard to recall precisely how A led to E. You could look at your web history, but it's an imprecise tool. If you happened to have a lot of tabs open and were multitasking — checking a bit of web mail, poking around intermittently on Wikipedia — then the chronological structure of a web "history" doesn't work. That's because there'll be lots of noise: You'll also have visited sites G, M, R, L, and Y while doing your A to E march, and those will get inserted inside the chronology. (Your history will look like A-G-B-M-R-C-D-L-Y-E.) Worse, often it's not until days or weeks after I've found a site that I'll wonder precisely how I found it … at which point the forensic trail in a web history is awfully old, if not deleted.
But hey: Why does this matter? Apart from pecuniary interest, why would anyone care about the process by which you found a cool site?
Because there's a ton of interesting cognitive value in knowing the pathway.
If you're reading this blog, you are probably least part nerd, which means you've likely read (or have heard of) Vanevar Bush's 1945 essay for the Atlantic Monthly, "As We May Think". Bush's essay has become famous amongst digital folks because of how eerily he predicted the emergence of a hyperlinked Internet. "As We May Think" is, at heart, a complaint about information overload (in 1945!) and a suggestion of how to solve it: By building better tools for sorting, saving, and navigating stuff. Bush envisioned a "memex", a desk-like tool at which you'd sit, reading over zillions of documents stored via microfilm. You could also write your own notes and reflections (which would saved in microfilm format too, photographed automatically via a forehead-mounted webcam "a little larger than a walnut".