Amazon Web Service (AWS) are a set of services hosted by Amazon that can be used to build and host your web applications at (potentially) a fraction of the cost of traditional hosting arrangements. I wont get into all the specifics of what AWS is, you can read that here. Basically, amazon setup an enormous amount of infrastructure and have services like S3 (Simple Storage Service) for remote distributed storage and EC2 (Elastic Compute Cloud) for resizable virtual computing (hosting).
