Data: $52/h (peak time, let's say 18 out of 24 hours) and $15/h (night time, let's say 6/24).
Edit: as pointed in the comments $30k/month would only be the EC2 costs.
It is also interesting that they seem to be using Akamai for a CDN instead of Cloudfront so not a completely AWS based solution.
I wish they went into what they are storing in S3. 410TB is a lot of storage. My initial guess was cached images but 80M objects breaks down to 5MB per object and that is a lot more than what is needed for image caching.
Looks like a switch to dedicated hardware would amortize within... 3 months.
Yes, they obviously have quite a few loose screws (read: whoever invested 100MM in that).
Either way, this is not a matter of "tightening". It's a matter of hiring an admin and having him not only pay for himself after 3 months, but for 1-2 other employees, too.
Yes, when you have 100MM in the bank then a mundane couple dozen thousand dollars a month might seem to matter less. But I can't think of a company where that kind of decadence has led to anything positive in the mid term.
No wonder 37signals decided to switch to their self-hosted storage solution.