There is a major market out there for smaller and smaller computers. Smartphones do an okay job but they do not have the software or memory of a laptop or desktop computer. Laptops are also a useful tool but they are far to big to keep discreetly in a pocket so those are out too. Now that those are both out of the picture we need to think of the smallest computer ( that is of any use ) that money can buy. Introducing the raspberry pi! This credit card sized computer is so freaking awesome that it uses linux software takes only a few watts and costs only $35. The only problem with these is that you must know more or less how to program simple command prompt style systems. This is because of the software systems that you must download and format. The best software to run this on is raspbian software which you can get for free on the raspberry pi site. The software goes on an sd card that is put in the raspberry pi.
This was only an introduction so stay tuned.