Maybe I use browsers differently to most people (I don't think so), but I really feel these features to manage tabs are misguided.
I get through thousands of tabs a week. Tabs don't indicate a web page is significant or persistent. They indicate that I wanted to have two pages open at the same time. Thus it makes no sense to manage tabs: they are an effect of untidiness, not a cause.
What these features are hinting at is some better way to handle common [sites]. I have a dozen or sites that I check every day, and being able to have those all open in one place would be great. But using the poor old tab system for this is not the answer. It already has a job.
Many people use tabs as a task queue. Particularly for sites like HN: someone sees several interesting things but doesn't have time for it right now - he opens it in a tab.
Just because tabs were meant for something else doesn't mean they shouldn't be used for this. If people use tabs this way, then by all means provide a feature to make it work better for this use.
I should point out that there really isn't anything good for this task other than tabs. You might say bookmarks, I say no. Until bookmarks (or some other feature) have a way to separate permanent bookmarks (like a site you frequently reference) from a temorary one (like the article you want to get back to soon) as well as the ability to very quickly remove the bookmark once you're done with it, tabs (or windows for those that have competent window managers) are the best solution right now.
I strongly believe in:
● space = area (programming, twitter, mail)
● window = subject, search, etc
● tabs = the subject expanded (pages relative to a search, links of an article)
Can you see? It has 3 levels of Hierarchy! If you use Google Chrome you have only one! This stacking thing is another trying to circumvent some OS's crappy UI. If something has to be done is go beyond the App centric paradigm and go to the 'task' center paradigm (like Palm OS's stacks).
Actually, all those things can be handled by a competent window manager. If you had the ability to have tags on your windows, and quickly change your view based on those tags, that would be Awesome.
I have Awesome window manager and Firefox with the Pentadactyl (and previously Vimperator) plugin.
I use Awesome's tag system extensively. When tabs aren't in use, the task list then looks and works like tabs - that is they are lined up across the top and you can click on them.
Not only do you get the benefit of the tagging, Awesome can be controlled completely by keyboard. I have mine setup to use Vi-style keybindings. Combine that with both Firefox and tmux using Vi-style keybindings, and you get a really cohesive, reinforcing keyboarding system.
It works great on my netbook for a couple of extra reasons: Firefox's chrome in this setup takes up about 20 pixels (for the status bar, and even that can be hidden if you want), and I don't have to use the horrible trackpad nearly as much.
I do prefer this, but I should point out that there are a few of gotchas to working without tabs. First, Firefox 3.6 is much slower opening a window than a tab. Firefox 4 improves this quite a bit, but it's not yet stable. Second, the Vimperator/Pentadactyl keystroke for opening a window takes two keys (";w") instead of one ("f"); this is probably fixable, but I haven't done it yet. Third, I haven't found a way to make a window open in the background yet; that means to open a window, it's ";w [link]...[mod+j]" - I open a new window then switch back to what I opened it from.
I'm using vimperator now, I didn't know about pentadactyl, thanks!
I actually don't bother forcing everything into windows, I'm fine with firefox managing its own tabs. In fact, I rarely have more than two windows on any one tag (and I really only select one tag at a time...kind of a "everything runs in fullscreen" mode for the most part).
Firefox 4 is doing something similar with its "expose"-like feature for tabs, that lets you group tabs in some way.
I too think it's silly, and I wonder if mozilla/opera are just building things because they think they're cool, or if they actually have user studies that show these are useful features. I expect the former.
I get through thousands of tabs a week. Tabs don't indicate a web page is significant or persistent. They indicate that I wanted to have two pages open at the same time. Thus it makes no sense to manage tabs: they are an effect of untidiness, not a cause.
What these features are hinting at is some better way to handle common [sites]. I have a dozen or sites that I check every day, and being able to have those all open in one place would be great. But using the poor old tab system for this is not the answer. It already has a job.