Touch sensors are commonly used in robots. When a robot runs into something, it comes in contact with a touch sensor to detect a wall and where to move next. Touch sensors can also be found in touch lamps for people with limited mobility. They are also found in mobile phone screens, touch screen tablets, or even special hand gloves for mobile phone users. Designers have used touch sensors in maps or pictures to light up places. 

Capacitive texting glove
Interactive map by Adafruit
Media art installation