A new feature in Visual Studio 2010 is called box selection, aka column selection, block selection, or rectangular selection. In the older versions of Visual Studio this was not possible. The only option you had was stream selection.

What this means is that you will not only be able to "copy/paste", "drag/drop", and delete box selections, but you will also have the new ability to insert and edit text on multiple lines.

Box selection allows you to manually select columns and lines at the same time.  Just hold down SHIFT+ALT+ARROW keys, and you’ll quickly get the feel for box selection. In addition to the keyboard method in the link, you can hold down the ALT key and drag with the mouse to get a rectangular selection of text.