S3 is an object-based storage service. It automatically handles scaling and redundancy. The multiple copies of files are made across multiple devices and locations automatically. Durability is extremely high at 99.999999999% over a given year. A single file can be from 0 bytes to 5 terabytes. Overage storage size is limited only by your bank account.

Objects are the base entity stored in Amazon S3, but you can think of it simply as a file that can be of (almost) any size or type. Everything is contained in what is called a bucket. Buckets are the highest level S3 namespace and are linked to the AWS account that owns it. S3 buckets are like internet domain names. Objects have a unique key value and are retrieved using a HTTP URL address.

Taken all together for analytics purposes, this means you can stuff tons of data there and not worry about backups, hard drive failures, or running out of space. It can be accessed easily using a URL-like format (assuming you have the correct security keys/permissions).