Quad9 is a public DNS service that aims to enhance user privacy and security by preventing access to malicious sites. Users often seek alternatives to traditional DNS solutions to improve their internet experience. The post highlights the importance of DNS quality, noting that users have had mixed experiences with different DNS services, such as NextDNS, unbound on OPNSense, and OpenWRT with Pi-hole. This reflects a growing trend among tech-savvy users who prioritize privacy and security in their internet usage.