Technet keys are generally Multiple use and may be used on up to 10 systems concurrently, I believe that this is the case with Technet Standard.
It has been decided that with packages such as Office, that there will be technet multi use keys for the complete packages but not for the individual components, such as word and excel Etc. this is I believe applied across all Technet Subscription levels except the specialist enterprise volume licences. This will mean a lot of reduction in the "available" packages, but for most people should mean no real reduction.
The legal position is a Difficult one, as people with keys obtained for products under the old system where the contract stated that the keys would not expire on termination of the subscription should still be covered by this contract, at least that's my understanding under English Law. Anything obtained under a new subscription would of course be covered by the new terms.