Touch screen software was initially used in kiosk systems, POS terminals, ATM's and on PDA's. With raising popularity of smart phones, modern PDAs, GPS's and portable game consoles, the demand for touch-screen technologies slowly increased.
Early touch-screen displays could only sense a single point of input at a time and only a few of them were capable of detecting the strength of the pressure. You can also get personalized screen displays by clicking at: https://mangodisplay.com/
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The movement of fingers creates gestures, which are then sent to the touch screen software. Popularity of iPhone, has brought touch-screen technology to many smart phones and hand-held devices.
Many companies have upgraded their products, either by adding a multi/touch support to the track-pad or by making their Tablet PC's interact-able without the stylus.
Some companies specialize in production of large wall-mounted or table surfaces. Most notable are Microsoft's Surface and Perceptive Pixel's Multi-Touch Collaboration Wall.
Developers of touch-screen systems, failed to notice, that humans are not built to hold their arms high for a long period of time, making small and precise motions at the same time.
Limited one-finger touch-screen capability has been available before, but Windows 7 is the first to deliver multi-touch. You can zoom in by placing your fingers on the screen and spread them apart.
Many companies produce specialized touch screen software, either for specific devices or for general computers. You can expect, from any decent touch screen software, to support multi-touch and gestures.