Technological unemployment occurs when technological changes (or more often advancements) cause traditional manual workers to lose their jobs.
For example when labor saving machines are introduced into the productive process, a company may lay off workers and produce the same amount of goods with greater efficiency but more importantly for less money.
Technological unemployment is considered to be part of a wider concept known as structural unemployment. Many experts believe this phenomenon has the potential to create mass, permanent unemployment.
"Software substitution, whether it's for drivers or waiters or nurses … it's progressing. ... Technology over time will reduce demand for jobs, particularly at the lower end of skill set. ... 20 years from now, labor demand for lots of skill sets will be substantially lower. I don’t think people have that in their mental model." Bill Gates 
"Technological automation displacing more jobs.
It makes sense to automate- more reliant, no strikes, much much safer, no wages to pay, 24hr operation as well as a number of other reasons. On the other hand cutting human labour ruins livelihoods and increases unemployment levels - creating an entirely new problem. In reality these increasing levels of unemployment are just another symptom of an outdated social system, along with the other 'symptoms' the world is currently faced with - such as the food, energy, financial and ecological crises.
The rate of new job creation resulting from technological automation is nowhere near enough to make up for the losses of jobs within that sector. Basically our economic system seriously needs to catch up with our technical capability.
We need to help direct and focus our attention on changing our world to be one of shared open access over private ownership. Work on eroding away our total debilitating dependency on money - necessary for survival and for access to nice things.
Just admitting there's a problem that needs solving is a good start."