Usually on a forum, when a user posts a very long block of text, with no paragraphs for separation, it is very difficult to read and looks like a "wall of text".

The full version is "China called, and they want their wall back" (Referring to The Great Wall of China), but is usually abbreviated to just "China called..."

Noun: a friend who is usually only called upon by a friend when a more primary/prominent friend is unavailable.

Taken from the term “second string” in an athletic competition situation. In football, if the star quarterback gets injured during a play, the second string is called off the bench to replace him/her. A “Second String Friend” is essentially benched until needed, if ever.

Synonyms: Plan B, Second Choice, Secondary Friend, Benched Until Needed