Column Selection can be used to select a rectangular area of a file. Column selection doesn't operate via a separate mode, instead it makes use of multiple selections.
You can use additive selections to select multiple blocks of text, or subtractive selections to remove a block.
Using the Mouse
Different mouse buttons are used on each platform:
OS X
Left Mouse Button + Option
OR: Middle Mouse Button
Add to selection: Command
Subtract from selection: Command+Shift
Windows
Right Mouse Button + Shift
OR: Middle Mouse Button
Add to selection: Ctrl
Subtract from selection: Alt
Linux
Right Mouse Button + Shift
Add to selection: Ctrl
Subtract from selection: Alt
Using the Keyboard
OS X
Ctrl + Shift + Up
Ctrl + Shift + Down
Windows
Ctrl + Alt + Up
Ctrl + Alt + Down
Linux
Ctrl + Alt + Up
Ctrl + Alt + Down
