reliability != durability. The article separately mentioned reliability/durability - "Go reliability and durability at Dropbox" "Dropbox hires engineers who ca

reliability != durability. The article separately mentioned reliability/durability - "Go reliability and durability at Dropbox" "Dropbox hires engineers who care about reliability and durability" for S3, in your link, there is very clear definition of the claimed durability, there is no similar definition in that dropbox article - "(S3) designed to provide 99.999999999% durability of objects over a given year. This durability level corresponds to an average annual expected loss of 0.000000001% of objects."