At other smaller stations, users must touch the card on a standalone validator.

On writing messages, the user must touch the screen in a certain movement or magical order to type out the letters.

The user should not touch the ladder at any moment with his/her feet.

The user can touch and slide to move up or down on the screen.

The iPhone 4 has an antenna that the user can actually touch.

When the user touched that spot, the video camera detected the movement and passed that data along to the computer.

With a special pen, a user can open up a clean "page," or touch the picture of a shredder to eliminate a file.

Neither users nor third parties should ever touch this directory.

Doesn't the idea that smudges will give you away kind of depend on the user never touching the screen other than when logging in?

Last summer, it was discovered that the iPhone 4's reception significantly dropped when a user would touch one of its antenna bands.