Pi-hole is a "DNS sinkhole that protects your devices from unwanted content". It's lightweight so it can run on pretty much anything including the original Raspberry Pi.
You can get basic stats about blocked requests at
http://<Your pihole address>/admin/api.php.
The dashboard is accessible at
http://pi.hole by default. You don't need to add it to your hosts file like I did.
Mac Apps #
- PiBar - Manage your Pi-hole(s) from your macOS menu bar!
- PiStats - macOS app to visualize Pi-hole information