If you're a serial mass tabber, like myself, it can be a pain organising said tabs into different windows, or even just ordering them. Chrome users, if you've been dragging your tabs around one at a time, there's a much, much better way.
As gHacks' Martin Brinkmann explains, you can move multiple tabs at once using shortcut keys. The first way is to hold down Ctrl and then click the tabs you want to move. Each will be highlighted, allowing you to simply drag them all to a new window.
The second method can be quicker, if the tabs are next to each other:
Select the first tab that you want to run operations on with the left mouse button, hold down the Shift-key, and left-click on the last tab that you want to include in the operation. All tabs between the first and last tab are included automatically.
I've been using Chrome since it came out ten years ago and I had no idea either of these existed, though I get the feeling they were added along the way. I'm not sure how often I'll be using them in the future, but I'm very glad I know about them now.