In a recent post on Call of Duty.com, the perks system for Ghosts has been detailed, shedding a bit more light on how you'll acquire them, and what they do. For starters, there are now 35 perks in total, all of which have a "weight value" of one to five. You'll get eight points to spend right away on perks if you have a fully geared loadout, but you can extend this number to 12 if you want.
Basically, this allows you to take everything off your person entirely, and go at it with 12 perks and a knife -- so it's pretty much the most customizable Call of Duty yet. Should you level up to a certain point you'll unlock these perks naturally, but you can also spend squad points to pay it forward.
I'm surprised it took them this long to explain it, and I have to say, as someone who has followed every Call of Duty launch for years, this is one of the least informative releases yet. We've gotten a lot of fanfare and even a music video, but as far as concrete information goes like this perk explanation, we don't have a whole lot.
Call of Duty: Ghosts [Call of Duty.com]