I like strava. I was standing around after a group ride and some guy came up to me and was like "hey I'm John, you took my KOM up in Talking Rock so I started following you on strava - you post some really great pictures"
We got to talking and he does a lot of gravel so I see him at every race I've done for the past two years - we talk turkey and compare times and routes and stuff. It's pretty cool.
I've also met a few other people by posting comments on their rides looking for advice on routes/water stops and so forth. I like being able to share my rides, sometimes my girlfriend looks at where I went and asks about something really specific about my ride. It's also nice to be able to easily track mileage and component wear for 6-7 different bikes.
I used to outline every road I've ridden on a giant state map, now I can just pull up my heat map and look at all my rides. There's tons of other things I like but I don't want to derail this thread.