Where can it be used ?

It can be used across variety of spectrum including computer vision, speech recognition, understanding natural language, understanding documents.

Deep Learning shines when there is a lot of data and often too complicated problem to solve.

History of Deep Learning:

1990 : A lot of work was done then. However major problems to its wide spread adoption existed because of  the slow computers and tiny data set.

Early 2000 : Completely Disappeared

2009 onward : Big comeback because of cheap GPU’s and lots of data. Nowadays deep learning is being used in any  situation which involves complex problem and lots of data

2009 : Gained Popularity  in Speech Recognition

2012 : Gained Popularity in Computer Vision

2014 :  Gained Popularity in Machine Translation .