It has already been put to use in humans. Some soldiers in Desert Storm received the subcutaneous chips so that they could be tracked and located if lost in the vast deserts there. As for the way that it will be sold to the masses for human use I will give but a few examples. First they will be offered in children to track and locate them if the are kidnapped, or something of that nature. As is happening with several "smart cards in use now, thhey will be offered as a non-theft device for financial transactions, health services and the like. There will probably be several well-timed hacking incidents that will "prove" that smart cards are a step, but the actual chip implants are the only way to prevent theft of money, identity, or what have you.
While there are those who feel this to be paranoia, those folks would be better served by preparing for it, or doing something to stop it. Just my thoughts, and no, MM, I believe in Creator profoundly and therefore have no damp dark fear-based actions in my life or diminishing my spirit.