Speaking in an interview with CNBC, DuckDuckGo CEO Gabe Weinberg said that the company’s traffic has grown 600 percent over the past two years. A variety of factors likely played a role in this explosion of growth, but it is mainly attributable to the NSA’s surveillance program, which was revealed two years ago, and Apple adding it as a default search option with iOS 8 and Safari 7.1 on the Mac. Google, however, has remained the default option.

With iOS 8, Apple added the option for users to choose DuckDuckGo as their default search engine within the operating system. Weinberg explained that this, coupled with increased privacy concerns, has led to extraordinary growth for his company. On iOS 8, DuckDuckGo joined Yahoo and Bing as an alternative to the default Google search

Google has stated in the past that a huge portion of its mobile search traffic comes from iOS. While Google is the default option, Yahoo and Bing have both tried in the past to take it.

Another big factor, however, is the growing fear that users carry when it comes to privacy.

DuckDuckGo heavily touts the fact that it doesn’t track the information of users and is a privacy-focused company. For instance, DuckDuckGo doesn’t offer any sort of personalized search like Google does. Google often catches criticism for its collection of user data, even though it continually promises that nothing is ever shared about its users. It has been reported in the past that the NSA tapped into Google servers and accessed the data of millions of users.

Weinberg says that DuckDuckGo is currently doing three billion searches a year. When asked how DuckDuckGo makes money without any sort of personalized search, Weinberg explained that the company simply uses keyword advertising. For instance, if you search for “car,” you’ll see ads relating to cars. Weinberg says that there isn’t a big enough difference between the revenue DuckDuckGo would make by tracking users compared to keyword advertising to justify the method.

Weinberg points out that users likely don’t realize how much data Google is collecting on them and what it is doing with that data. This is how DuckDuckGo will continue to grow and win over customers, Weinberg says.

The revelation of the NSA’s surveillance program two years ago opened the eyes of many users to the fact that they need to worry about privacy. In many ways,  deservingly or not, Google has bared the brunt of privacy concerns and allegations and that’s further shown by the growth of DuckDuckGo over the past two years.

You can watch the full interview with DuckDuckGo CEO Gabe Weinberg here.