[bdonlan]

> I would imagine that Dropbox pays some sort of bulk price, but I can't find any information.

Storage pricing is right there on the S3 pricing page: http://aws.amazon.com/s3/#pricing

Assuming they're at the highest tiers, we're looking at about $0.055/gb storage, $0.050/gb transfer out, $0 transfer in. Transfer out could certainly be less, though, if they're in the >524TB/mo range.

[natrius]

I'd bet that Dropbox is that largest S3 user in existence. Custom rates are very likely.

[EliAndrewC]

Netflix also uses Amazon S3 and is probably an even larger customer, but I agree with your assessment that custom rates are very likely (for both of them).

[jonknee]

Netflix uses EC2 for computing power. It uses CDNs (Level 3 and Akamai mostly) to deliver streams so most of the bandwidth would not be from Amazon.