Actually, I believe there is more to the NDA that what Ninja is indicating...
The 6 month, 1 yr, or 2 yr expiration is typically to ensure the technology simply does not get into competitors hands.
There are typically other "riders" that indicate the product can NEVER be re-sold, etc...
This is because there is no warranty (it's a free ES...) what-so-ever on these ES chips - thus if one gets into the hands of someone (like LordGeek) and that chip dies, it can become a publicity nightmare for Intel (if the person were to be a jerk about it, etc... - problem is Intel can't tell where the chip really came from... could have been the person claiming Intel sold them a bad chip really robbed the truck the chip was on - an example not related to this ES example, but similar...)
Either way - those chips are never for re-sale...