(Editor’s note: This is the introduction to Laurel Rosenhall’s reporting on California privacy laws written for CalMatters. The series consists of ten pieces diving into and explaining the privacy laws. You can find the series here.)

Our actions online have created a vast trove of information worth billions of dollars. Every time we search, click, shop, watch, send, receive, delete or download, we create a trail of data that companies can use to figure out our tastes and interests. We also hand over information when we use social media or loyalty programs at our favorite stores.

This data has formed the foundation of the internet economy, allowing advertisers to better target the people they want to reach — whether that’s a company that wants to sell you something or a politician who wants your vote.

But many Americans have grown concerned about what else can happen with all this data. Hackers have stolen it from email providers and credit card companies. Facebook was fined $5 billion for mishandling information on millions of people that political consultants exploited to influence the 2016 presidential race. Health apps have been criticized for sharing their users’ most intimate details — including when they have sex or ovulate.

Responding to outcry that technology companies have invaded consumers’ privacy, California became the first state in the nation to pass a law giving people more control of their digital data. The new rules take effect on January 1. This explainer will walk you through what California is — and isn’t — doing to give you options to protect your privacy.

Continue to the series on California’s Privacy laws here.