A couple of days ago, I was doing some research on the web. It was totally run of the mill stuff: opening a bunch of windows each with countless tabs and then jumping back and forth between them in order to compare or capture certain aspects of a bunch of different similar things. In this case, I happened to be trying to find a Ruby class that would help me help with screen scraping (Rubyful Soup turns out to be the best solution, if you're curious), but I might as well have been looking for indie rock music venues in California near universities, the submission email addresses for mp3 blogs that might write about my band, or maps of apartments around town that my shiftless basement-dwelling sub-leaser could rent. We've all done this kind of thing. A lot of us do some task that involves this kind of workflow on a regular basis.
One problem that pops up in a task with this structure is: You're looking at a link. Is it already open in one of those other zillions of tabs marching across any of your quadrillion open windows? And if so, which cotton-pickin' one? Now, your browser will tell you whether or not you've visited the linked page before by changing the color of the link's text, but is that tab still open? And where is it? These are harder questions.
It seems pretty obvious that the browser should help you out here. What are the odds, really, that you want to have the same page open in more than one tab? The default behavior when clicking on a link to a page that's already open should be to bring that open tab to the front. You could probably write an Applescript (or use Greasemonkey if you swing that way) to hack your way to this behavior, but it would certainly be nice if these so-called modern browsers would step up and handle it. If we're going to have a browser war, at least we could get some tasty conveniences out of it!