Unfortunately a lot of details are missing:
- what kind of data is stored?
- why do they need 9 billion live documents?
- how much of that is really accessed on a daily basis/monthly basis?
- hardware, infrastructure, deployment details
If someone knows more about these, I’m sure the NoSQL community would be gracious to hear them.
Update" Tony Tam (@fehguy) pointed out a presentation about Wordnik which adds some little info to the above questions: