Facebook is least important for people in your situation (still in school). You can't help but physically interact with most of your social circle, as you sit in the same building as all/most of them on a daily basis.
For those of us who are older and out of school - I don't live in a city with any of my family, many of my best friends are (literally) all over the world. In the past, we'd just (most likely) drift apart / lose contact. Now? We can stay completely up to date on each other's lives, talk/communicate daily, as if we were at the bar carousing late into the night, as we did 10-15 years ago. These people are important to me, but there is literally no way to talk to them in person, without spending $$$$ on plane tickets/etc.
Actually, your use case was the #1 reason for my problematic proclivity toward Facebook. I too have friends from all around the world (people I worked with on open source projects, people from programs and schools I used to attend, etc). It was because of these connections that I felt attached to Facebook -- I couldn't exactly bump into someone living, as you suggested, vastly out of my proximal social circle.
How have I delt with this? Well, I'm not completely sure. For some who I am particularly close to, I text or IM them on occasion. To keep in contact with a few people, I actually created a new Facebook account with only those people as friends, and then only used the account as an IM client via Facebook messenger.
Honestly, the latter idea makes me wonder: maybe the reason my Facebook experience was so problematic and low S/N was because I (due to typical social pressue) was friends with way more friends than I genuinely want to stay in active touch with?
I don't know. You make a good point, and clearly I don't have a good answer; I've addressed those needs on a case-by-case basis.
If I can dream for a bit, I think my ideal technology solution to this would either be teleportation or immersive 3D video conferencing. It'd be pretty damn cool to "grab lunch" and catch up with someone on the ohter side of the world.
For those of us who are older and out of school - I don't live in a city with any of my family, many of my best friends are (literally) all over the world. In the past, we'd just (most likely) drift apart / lose contact. Now? We can stay completely up to date on each other's lives, talk/communicate daily, as if we were at the bar carousing late into the night, as we did 10-15 years ago. These people are important to me, but there is literally no way to talk to them in person, without spending $$$$ on plane tickets/etc.