Strava "lets athletes all over the world experience social fitness – sharing, comparing and competing with each other's personal fitness data via mobile and online apps."
It's a fun way to log your mileage, particularly if you're training for an event, or working to reach a particular fitness goal. Even for those who only ride "for run", Strava is a great way to follow what other cyclists in your community are doing, and perhaps be motivated by their rides and accomplishments.
The key feature Strava pioneered is the concept of "segments" – a particular section of road or trail that cyclists can ride, and compare their results. It give you a taste of competition, even if you have no interest in competing in actual races. It's a cool way to help make familiar routes fresh, and it can even help you discover new roads, trails, and routes you might not have ridden before.
Feel free to join the Kansas Cyclist Strava Club if you feel like it, and share your rides with other cyclists in this online community.
Also, a fun resource, which uses Strava data to show the places people ride most, is the RaceShape Heatmap.