Ads are annoying. Not only when trying to read morning news and more than half of the website is spammed with moving gifs (or flash ads, the worst kind of ads), but also they are able to spy on you and track you browsing behaviour.
Of course, most people are using browser extensions like Adblock Plus or (my favorite) uBlock Origin. But what about your devices that do not support extensions? For instance, I own a Samsung Smart TV and there is no way Samsung is letting me install some privacy enhancing apps. This is exactly where Pi-Hole comes in.
Pi-Hole is a service meant to run on a Raspberry Pi (we all have at least one, right?) and serves as a DNS server in your local network. Instead of resolving all hostnames without thinking, like your router or any other DNS server would do, Pi-Hole has a Blacklist of malicious domains providing either Ads or Trackers. These domains are not getting resolved, preventing any device to access them as long as they are trying to reach by hostname and not by IP. By entering my local Raspberry Pi as DNS server address in my Samsung TV, I found out that it was spying on me. A lot. There were several requests every few seconds, trying to reach log-ingestion-eu.samsungacr.com. ACR in this URL stands for “Automatic Content Recognition”. So my TV was trying to gather data on what I am watching, when and how long. I’m glad I can prevent this from now on; shame on you Samsung!
At the same time, I technically don’t need a AdBlock plugin on my browser anymore, saving some memory and CPU (like 0.1%). The better thing is, many websites that aren’t meant to be accessed by AdBlocked browsers still work with Pi-Hole, since the blocking mechanism works different than in browser extensions.