Well. This is an interesting thread.
What I'll say is that the data posted in this thread is proprietary in the sense that NPD's clients pay nearly $10,000 each month just to have access to them. Clients are not allowed to 'leak' that data as per the agreement they have with NPD.
If someone, such as Librarian13579, wishes to post NPD data publicly then they are doing so with the risk that the NPD Group could investigate and find them in breach of contract. This could result in NPD suspending their agreement with the client who leaked the data and could also lead to Librarian13579 losing their job.
I don't think some of you understand how serious these situations can be. There is a legitimate reason why Librarian13579 doesn't want these numbers all over the internet, especially when it can lead to the NPD Group investigating further. I've seen this happen in the past where leakers will try to obfuscate and slow the spread of numbers so that the NPD Group doesn't catch on. Creamsugar being one example. People like Ethomaz, who have displayed this sort of behaviour before, do not help by spreading the numbers far and wide as soon as they are leaked.
That being said, I don't personally think anyone should risk their job by posting NPD numbers publicly, especially when under NDA. Given the events that have transpired today I wouldn't expect Librarian13579 to post numbers again in the future. I'm conscious that the community here is interested in the numbers but everyone needs to understand exactly what's at risk to leakers, why they do it and what the potential consequences are.
Personally I would love NPD to be more open and share numbers themselves, but that won't happen due to various agreements between NPD and retailers / publishers. In the meantime the general public has to rely on leaks, but that won't happen if leakers can't do so safely. The NPD Group has long tried to crack down on leaks coming from places like NeoGAF with high traffic. This is because leaks posted to NeoGAF spread quickly across the internet and become common knowledge across many. So the NPD Group is more likely to exercise its legal right to clamp down on leaks if they get posted everywhere.
But anyway, I've already said I don't think people should leak data. But I'm just giving you all an explanation about those that do.