Google and Facebook collect information about us and then sell that data to advertisers. Websites deposit invisible ‘cookies’ onto our computers and then record where we go online. Even our own government has been known to track us. When it comes to digital privacy, it’s easy to feel hopeless. What power do we possibly have to fight back?

“Everyone has different concerns,” wrote Jamie Winterton, a cybersecurity researcher at Arizona State University. “Are you worried about private messaging? Government surveillance? Third-party trackers on the web?” Addressing each of these concerns requires different tools and techniques.

“The number one thing that people can do is to stop using Google,” wrote privacy consultant Bob Gellman. “If you use Gmail and use Google to search the web, Google know more about you than any other institution. And that goes double if you use other Google services like Google Maps, Waze, Google Docs, etc.”

The ads you see online are based on the sites, searches, or and Facebook posts that get your interest. Some rebels therefore throw a wrench into the machinery by phony interests.

It’s perfectly legitimate, by the way, to enjoy seeing ads that align with your interests.

But millions of others are creeped out by the tracking that produces those targeted ads. If you’re in that category, Winterton recommended Ghostery, a free plug-in for most web browsers that “blocks the trackers and lists them by category,” she wrote. “Some sites have an amazing number of trackers whose only purpose is to record your behavior (sometimes across multiple sites) and pitch better advertisements.”

Most public WiFi networks are eaves-droppable, even if they require a password to connect. Nearby patrons can easily see everything you’re sending or receiving – email and website contents, for example — using free ‘sniffer’ programmes.