Please don't assume this is a one-time event, or that it is specific to this brand or even to Chinese manufacturers. Nokia could actually be in the best half on that aspect, just got unlucky. Most of such info leaks are hidden. I've already witnessed several OEM firmwares sending informations to many different parties. Too often, this is done through http, with payload encrypted. But it's always symmetrical encryptio…
Out of curiosity, what "advertisement" company would that be?