Processing power has increased, data storage is increasingly cheap and algorithms to analyze that makes sense of all the data exist and are continuously refined.
Smartphones, camera and other devices are connected to the Internet (defined ioT Internet of Things) and continuously capture data. Websites track our interactions and preferences, what we like and do not like; who we interact with and who are our friends. Google, Facebook and other services know where we live, where we work, the road we take and many other things.
In most cases, aware or not, we give this information for free in return for the services. These service monetizes our personal information by showing us ads or selling our info to other third party that will aggregate it and make sure they can make money out of it.
Our info is analyzed not only for commercial reasons, but also by governments that intercept and analyze Internet traffic and more.
A couple of examples:
Get your loved ones off Facebook.
Are you heading toward a big brother scenario? Is there a way to defend ourselves?
Some tools: