I have not been able to start using G+ actively, since it took quite a time for me to come up with nice circles definition, that is
1) MECE (Mutually Exclusive, Collectively Exhaustive)
2) Fits into memory - no more than 5 groups!
3) Sizes of circles are well-balanced
Inspired by sociologist Mark Granovetter's idea of 'weak tie', I think now it is done quite elegantly:
1) Koreans - who are not annoyed because I am posting in Korean
1-A) Korean Strong Tie - those I can speak international matters with
1-B) Korean Weak Tie
2) International Friends - those who don't read Korean
# 2-A) International Strong Tie
# 2-B) International Weak Tie
Currently 2) is kinda small relative to 1), thus 2 is not yet sub-divided into 2-A) and 2-B).3) Family
But still, I need yet another rule to decide on which occasion should I use facebook/twitter/G+. Man, using SNS is quite a burden!