I heard some rumors of a spin-off show, but initially dismissed them as a fanboy pipe dream. However, it appears they really are planning to make a second TV series based in the same universe:
I'm probably the only one who didn't know this, now that I think about it.
Now I'm wondering if Carol will be an anchor character for the new series; so they can make sure audiences understand that it's the same world and the same rules apply.
Anyways, it sounds like a cool idea to me and I think there is great potential for the new show as long as they keep the events of that series far away from Georgia. Similar to how they had three CSI shows set in Las Vegas, Miami and New York.
I'm hoping that they set it somewhere that is geographically very different from Georgia. Maybe even around Albuquerque, New Mexico where Breaking Bad took place. They already seem to have a good relationship with the New Mexico state government, so why not continue using the location? Although, considering how New Mexico is a sparsely populated, desert state, it doesn't really lend itself to having massive herds of zombies walking around. In fact, last I checked, sheep and cattle still outnumbered people in New Mexico 2 to 1.
I just really hope it's not a prequel and that the events of the spin-off show run concurrently with the existing show.