What is it?
Pi-Hole is software that blocks ads on a network level.
Basically, you install Pi-Hole on your Linux machine (typically a Raspberry Pi) which turns it into a DNS server. You can then connect either your router or a specific device to the host machine via their DNS settings.
Once set up, all your traffic will be routed through the host machine, and it will block any URLs associated with ad networks.
Does it Work?
Technically, it does work. But it does have some exceptions. It is not able to block YouTube video ads and other video ads on some websites.
It is possible to find some blacklists that users have created, though they often do not work. If they do work, they usually also block things you don’t want blocked. For example, a blacklist may successfully block most video ads, but it may also screw up thumbnail images, your Google Drive, etc.
Should You Get It?
I think of Pi-Hole more as a network security tool than anything else. Since it blocks ads at a DNS level, any malicious ad won’t even be pinged by your Internet.
This also accelerates page loading, since your Internet does not have to load as many things when you navigate to a URL.
So, I think you should get Pi-Hole, but maybe think of it less as a complete ad block solution (it’s not) and more a security measure that also happens to block most ads and speed up your Internet.