Research shows mass surveillance is causing a decline in free speech over the internet. Read the latest episode of our series to learn more about the 'spiral of silence'.

Since Snowden's revelations, journalists and writers have been self-censoring on a wide range of issues - and this is just one of the 'chilling effects' of mass surveillance.

During this series we've learnt about mass surveillance, privacy and democracy. But how do they all fit together?

Opinion shapers don’t just develop new ideas that may become social rules. They also create new information on how existing rules are being applied in practice - something called democratic accountability. To do so they need privacy - here is why.

In this episode we explain that without privacy, we would have fewer new ideas and fewer new rules. Privacy allows opinion shapers and social innovators to shake things up and change majority views.

Privacy frees us from the constraints of social control. Because of this, it gives us the freedom to think critically, question social rules and debate ideas that might be considered controversial.

Governments tell us that if we have nothing to hide, we have nothing to fear from mass surveillance. Why is this misleading and devious argument so powerful? How can we beat it?

Why? Because it's useless and it's dangerous. Only traditional methods of gathering intelligence have helped security services stop terrorism. Mass surveillance, which doesn't produce results, is draining resources away from tools that actually work.

Mass surveillance is ineffective because it weighs down security services with so much information that it's impossible for analysts to identify what is important or relevant.

Encryption is a very old technique. It just refers to the process by which we can hide the meaning of something by using a code. We explain how it helps protect our privacy and our money, and how authorities are using hacking to get round it.