It seems there has been one sure winner out of last year's NSA PRISM spying scandals. Privacy-centric search engine DuckDuckGo serviced one billion searches in 2013, due to a boom in Internet users' interest in secure search engines.

In fact, DuckDuckGo has experienced an almost doubling in traffic since the revelations of US government spying by whistleblower Edward Snowden.

DuckDuckGo distinguishes itself from other search engines by not profiling its users, and deliberately showing all users the same search results. Its mission is to protect its users' privacy, but also avoids the so-called "filter bubble", whereby a search engine guesses what information a user would like to see based on information such as location, past click behaviour and search history.

It also encrypts all searches by default, which Google only began to do in September, in the wake of the spying scandal.

"Needless to say, it was a great year for us," the company said in a blog post. "We have a lot of big things planned for this year that we hope will address a lot of the excellent feedback you have been giving us for some time. So please stay tuned."

Originally founded by Gabriel Weinberg, an entrepreneur whose last venture, The Names Database, was acquired by United Online in 2006 for $10 million (£6.1 million), DuckDuckGo attracted more than 4 million daily users by November 2013. That's up from just below 1.5 million queries each day before Snowden's leaks hit the press.

By comparison, Google processes over a trillion (1,000,000,000,000) search results each year.

Other secure searching services have had a strong year, too. StartPage, which offers Google results through a proxy that allows for anonymous searching, and Ixquick, produced by the same company but offering results from multiple search engines, have boasted 4 million direct private searches a day.

In the wake of the Snowden revelations, Weinberg told CNBC, "we always knew people didn't want to be tracked, but what hadn't happened was reporting on the private alternatives, and so it's no surprise that people are making a choice to switch to things that that will give them great results and also have real privacy."

That switch seems to be taking hold in at least some sectors.

Speaking about other Silicon Valley giants being compelled to hand over data to government agencies, Weinberg said "We had zero inquiries and the reason for that is because we don't store any data. So if they come to us — which they know because it's in our privacy policy — we have nothing to hand over, it's all anonymous data."

At the time of writing, DuckDuckGo search stats do not appear to be publicly available.

Image: Flickr (@Doug88888)