It used to be that in order to track marketing success (or failure), brick and mortar stores would hand out paper index cards to survey their customers. This method manually collected static data such as customer names, addresses, items purchased and satisfaction levels.
This information then had to be sorted and analysed by hand, which was not only time-consuming and monotonous but also relatively useless. Or, at the very least, did not paint the full picture of consumer trends. Now, thanks to the internet and a few new technologies, it has become possible to aggregate thousands of micro-observations by tracking the digital traces created by a person’s online behaviour.