Recently, I've been looking at San Diego on Google Earth. I've noticed a large amount of sprawl in a sort of ring stretching from La Jolla, past Poway and on to Escondido and Vista, where it meets up with Carlsbad and Oceanside on the sea and continues down back to La Jolla. So I was wondering whether this area is considered part of San Diego or if it is simply considered a number of communities north of the city, seperate from the rest. Just wondering. :)

Only La Jolla is within the city limits of San Diego. The other places you mentioned comprise of our sprawling suburbs, which are definitely part of the CSMA. That area is referred to as North County.