"The idea behind Data Lake is — as the name implies — to give developers a single place to store all of their structured and semi-structured data in its native format without having to worry about storage and capacity limitations on individual files."
Data Lake @ Azure
"Azure Data Lake includes all the capabilities required to make it easy for developers, data scientists, and analysts to store data of any size, shape and speed, and do all types of processing and analytics across platforms and languages. It removes the complexities of ingesting and storing all of your data while making it faster to get up and running with batch, streaming, and interactive analytics."
Introducing Azure Data Lake | Microsoft Azure Blog
Behind the scenes of Azure Data Lake: Bringing Microsoft’s big data experience to Hadoop | Microsoft Azure BlogRAGHU RAMAKRISHNAN, Technical Fellow, Data Platforms
"... Microsoft made it official: The technological underpinnings of the coming Azure Data Lake service are based on the very ones that the company uses internally as part of its "Cosmos" big-data storage and analytics service."
Same as Amazon AWS, Microsoft provides same Azure services it uses internally.