Okay ... Facebook will, by default, share your location with nearby friends unless you turn off the feature.
What's nearby friends? Glad you asked. It is where Facebook is using the geolocation info from your phone to report where you are and if any of your pals are nearby.
Intrusive? Maybe! If you want to turn it off, here's what you do:
1. Sign into your Facebook app on your phone.
2. Go to More and select Nearby Friends.
3. Now, once there, go up to the gear on the right hand side:
4. And then turn off Nearby Friends:
Aw you're such a party pooper.
Anyway, if you ever wanted to turn it back on, you could. Just reverse the steps and flip the switch. You'd be the life of the party all over again.
Remember: it's not that Facebook's evil, they just think you want to be the most public person possible. You're able to control this capability on your own. That's a company thinking about privacy as an option :)