Almost everyone knows you can tear off and re-join tabs in Chrome, but it also supports powerful docking features that are quite useful, especially on Windows XP and Vista (which lacks the window manager refinements of Windows 7).
The most useful feature probably is the ability to drag a tab to the middle of the left or right edge of the browser window (as shown below) and have the windows arrange themselves into a vertically-split view that’s ideal for side-by-side comparisons.
There are more docking positions listed on Chrome’s help pages.