One of the most frequently asked questions on social media on Friday was: what is DDoS?

DDoS stands for “distributed denial of service,” which is tech jargon for what happens when hackers flood a computer on the internet with information requests, causing it to overload. This simple sounding technique is what was responsible for the shutdown of websites in the US and Europe over the weekend.

DDoS attacks may sound simple, but there is a lot going on behind the scenes. To create a DDoS attack, hackers use something called a botnet, or a network of infected personal computers, servers, smartphones and other devices that can be controlled remotely.

When activated, the botnets start requesting web pages from specific servers, targeting their unique Internet Protocol (IP) address. These requests can force those servers to process upwards of hundreds of gigabytes of information per second. A hundred gigabytes is the rough equivalent of 25,000 music files. This attack simply stops virtually all legitimate requests for web pages from getting through.

Friday’s DDoS attack targeted servers owned by Dyn DNS company, a company that oversees the web traffic of several major social media sites, including Twitter, Reddit and Spotify. When Dyn’s computers were attacked, it made both the servers and all the social media traffic that usually flows through them unavailable.