1. The NSA’s Surveillance Algorithm
The NSA’s surveillance programs work, or so they claim, by collecting metadata: not the content of your phone calls and emails, but their length, who they connect you to, and when they happen.
2. Encryption Algorithms
Another way to combat surveillance is to confuse the algorithms—turning their own capabilities against them. Encryption algorithms encode your data, using a secret formula to turn it into an unreadable mass that entities like the NSA can’t process. That’s how post-PRISM services like Silent Circle and Least Authority protect their users’ phone calls and messages from snooping. But encryption algorithms have a very long history.
3. Google Search
If you’ve ever had Google fill in the rest of your search text like a mind-reader, you’ve also experienced an algorithm at work. Compounding what you’ve previously searched with what other users search for every day, Google’s algorithms can predict what you’re looking for with a frightening degree of accuracy.
4. High-Frequency Trading Algorithms
In the heyday of Wall Street, traders shouted across exchange floors to buy and sell stocks. These days, it’s a whole lot quieter—around 50 percent of trading is done by firms specializing in “high-frequency trading” (HFT), which refers to rapid-fire share buys and sells carried out by computer programs rather than humans. Hedge funds that specialize in HFT develop proprietary algorithms to determine what they buy and sell and when, then the programs carry out those instructions in milli- or microseconds.
Algorithms influence even our intimate relationships. The now-iconic surveys of OKCupid, the question-and-answer sessions the dating site spews out to help match its users, provide the data for the site’s compatibility algorithms.