I did that throughout my early 20s. I'm still in regular contact with people I met 14-15 years ago. It takes effort for regular stuff. The only reason I keep my Facebook around is because it's a glorified address book and I'll hear from some of the folks from my past travels on there around holidays and birthdays. It's about the same as I talk to cousins and aunts/uncles.
My core group of friends is in touch all the time. About 12 people since 2001. I don't talk with anyone from high school (pre-01).
It just depends on your level of effort. I think for American kids, it's definitely worth getting out into the world and seeing a different perspective. It can only improve our country when we get outside the rhetoric/news bubble and see how things are done, for better or worse, in the rest of the world.