Let’s talk about Google’s new web history feature for a minute. This is a product that helps personalize your search results and it’s useful for that alone, but I wanted to highlight a couple examples of other ways it can be handy.
Example 1: What was that helpful site? A month ago, my wife was working in Adobe Illustrator and wanted to make an oval vignette effect. We figured out how to do it, and I promptly forgot how we did it. Last night, my wife wanted to do the same effect. Crap. I didn’t even remember the name of the Illustrator feature we used. So I go into web history and did a search for [illustrator]. I sorted by date, and there’s the stuff that we found three weeks ago:

It turns out that Illustrator 9.0 introduced a couple new features: layer clipping masks and opacity masks. By the way, if you reach this page searching for how to make vignettes in Illustrator, this page has a good compare and contrast about layer clipping vs. opacity masks and this page is a good tutorial on opacity masks.
My point is that I knew a keyword that I’d searched for weeks ago, so searching my history for [illustrator] told me that I’d done a bunch of Illustrator searches on April 3rd, and showed me the results that I’d clicked on while doing research the first time. That made it easy to re-discover that “just right” page that had helped me before.
Example 2: What was my timeline of viewing web results? I browse in a particular way in Firefox. When I’m reading an article and a link looks interesting, I open that link in a new tab in the background. That works great, except when I end up with 30 open tabs. Last week I ended up on this site called http://gotads.blogspot.com/. John K has a lot of thoughtful posts and before I knew it, I’d read a few months’ worth of his blog. But I’d forgotten: how did I find his site? Was it from a comment link on Battelle? A blog search? ThreadWatch? I didn’t remember. I’d opened John K’s site in a new tab, so I couldn’t tell where I’d opened it from.
I can hear you now: “Matt, you idiot! Why don’t you have Duplicate Tab installed? Or some other Firefox extension that clones a tab and preserves its history?” Sure, I agree, but at that point it was too late to install an extension. So I used my web history and looked at which things I’d opened most recently. Ah, there it was. I’d noticed the site on Techmeme and then surfed away from Techmeme. The timeline feature of web history is very handy to help you remember how you got to a web page.
Google’s web history feature is useful for personalization (that’s why I enabled it), but it can help in lots of other ways too. It’s a lot like the original Memex paper (which everyone should read):
The owner of the memex, let us say, is interested in the origin and properties of the bow and arrow. Specifically he is studying why the short Turkish bow was apparently superior to the English long bow in the skirmishes of the Crusades. He has dozens of possibly pertinent books and articles in his memex. First he runs through an encyclopedia, finds an interesting but sketchy article, leaves it projected. Next, in a history, he finds another pertinent item, and ties the two together. Thus he goes, building a trail of many items. …. Thus he builds a trail of his interest through the maze of materials available to him.
My session of Illustrator queries and clicks looks a lot like one of those trails of interest to me. I like that much like Google Notebook, Google Web History provides a way to easily get back to research you’ve done before. In the last few days, it’s already helped me a couple times, which is pretty nice.
P.S. If it’s the personalization you’re interested in, Google OS did a prescient post a month before the feature even launched. And Danny did an in-depth write-up after the feature launched.
