(Disclosure: I work for Google, but not on Chrome or anything related to this post.)
Tabs have become a critical part of browsers, and are also supported in other apps like the Finder and some text editors. But they are somewhat primitive in their design.
To begin with, it’s good to see Safari and Finder adopt a “Merge All Windows” menu item. Unfortunately, Chrome and Firefox don’t, which goes to show that support for “Merge All Windows” is not yet universal. This is unfortunate. Combining windows should be a universal operation in any app that supports both tabs and multiple windows. It’s a more automatic and less fussy version of manually dragging tabs into windows.
We also need the opposite, which is to handle windows with too many tabs. I should be able to tell the browser to automatically split a window into two or more windows. Tabs can be grouped based on the site. That is, if I have a window with 30 tabs open, 15 from The Economist and 15 from The Verge, the browser should intelligently split them into two windows, one for each site. Another heuristic would be the time when those tabs were opened (“Tabs from this morning”, “Tabs from yesterday”, etc).
The browser should also intelligently decide how many windows to create, again based on the number of tabs, to keep each window manageable. For example, if I have 15 tabs from The Economist open, maybe that’s best split into two windows. But if I have 25 tabs, maybe three windows is best.
Whatever the details, the browser should be able to automatically split an overflowing window into multiple windows to keep things manageable.
Then, I’d like to be able to save a whole window’s worth of tabs to Instapaper or Readability with one click, and then that whole window, to keep things manageable. People have a limited ability to multitask, and exceeding that causes inefficiency, anxiety and stress. Not to mention that I don’t need to read dozens of things simultaneously. One after another will work just fine, as with Instapaper. It’s not as if I’m going to make a major decision in a minute, and so need to read everything right now.
Finally, I may want to push a tab to another device. Say I’m reading something at home on the weekend, and I realize it’s work-related. I might want to send that tab to my desktop at the office, and close it on my laptop. Conversely, I’m in the office, reading something, and I realize it’s better done at home, or I’m about to leave the office, in which case I should be able to send it to my laptop. Another use case is: if I come across something interesting on my phone, but don’t want to read a desktop web page on a tiny phone screen, I might want to send it to my laptop .
Chrome currently offers a pull model, where you can see what you have open on other devices, and open those pages on the device you’re using right now. That’s good, but I also need a push model.
Tabs are primitive. They need a lot more thought and work put into them given how important they’ve become. Browsers and other apps need to do better at combining tabs into windows, splitting windows, saving to read later, pushing tabs to other devices, and so on.
 Chrome simply gives up if you have too many tabs open:
(please Cmd-click the screenshot to open it at full size)
Each tab is so small that you can’t see what a tab holds before you switch to it, which defeats the point of tabs as a way to switch between multiple web pages in one window.
Safari shows an overflow menu if you have too many tabs:
This is better than Chrome’s implementation, but still awkward. When you select a tab from the overflow menu, it shows in the last tab that fits on the screen. That is, there are 13 tabs visible on screen, with the rest in the overflow menu. The first 12 of these tabs behave normally. The 13th tab on the tab bar is used to show which ever tab is selected from the overflow menu. This breaks the 1:1 correspondence between tabs and loaded web pages.
Safari also has a “Show all tabs” option at the extreme right of the menu bar, which I thought will show me all my tabs at once, but it shows only three at once, which is even worse than the tab bar:
Who needs such a broken overview? Safari should work like Mission Control in OS X, showing you all the tabs at once.
Firefox’s implementation of tabs is perhaps the most sensible, merely scrolling the tab bar, avoiding the problems with the Chrome and Safari designs:
 Bookmarks don’t work for this, since they are synced and show up on all devices, defeating the point of bookmarking it. I end up emailing URLs to my work ID, which is an ugly, manual solution to the problem.