朋友, explained by someone, who is eurolized as "the Contemporary Xu Shen", is that as friend, they need to communicate atleast onece a month, I felt this kind of 望文生义 by common sense.

Today I found the possible correct answer, that is as friend, they are in same aspirity, interest, etc. a little bit similar with comrade...I leave the complete analysis for you.

Xu Shen's words are that 朋 is pictograph of a bird, like 鹏 or phoenix. This gaves us a base. The question is why not other bird, like owl, swallow, crain, eagle like our XYFY? My explanation in this word may not be labeled as irrelavent in the future if I present a serial words.

My friend, wish you 鹏程丌里!