In simple terms, AWS is nothing but an infrastructure solution that provides storage, computing, database, security and networking services for anyone who has or wants to start a business/application without the hassle of investing in the above necessities. Thus cutting major business capital expenditure and diverting them instead to other resources.
AWS is a platform for launching and running big data applications. As a Data Scientist you can use AWS to leverage their visualisation tools and wizards that already contain ML algorithms to run against your data and do predictions on them.
Some of the major customers that use AWS services are: Cloudera, Netflix, Expedia, Unilever, and many others.
I think you'll find all the information you want on Amazon Web Services (AWS) at the link below:
At the above site they got a tonne of videos, tutorials, white papers, self-paced labs, web-based training, and webinars to clearly understand and learn AWS. You can learn it at your own pace in a few days. You can start using their services for FREE by creating an account on their site.
Here's a youtube video on introduction to AWS:
And their youtube channel:
After learning AWS you can even take a AWS certification. Here is the FAQ link for AWS certification:
And more information on Analyticsvidhya.com at this link:
You can Google for more information on AWS. Its a vast ocean and ever so expanding.
Hope this helps!
All the Best in your job search.