In a question from Stack Overflow meta, the questioner has a heading:
This is currently just blue-sky thinking
in which he's tossing around ideas and asking for feedback or a brainstorm, so they can work out what direction might be good to take.
As defined by the Collins Dictionary:
Blue-sky thinking is the activity of trying to find completely new ideas.
Some consultants are good at blue-sky thinking but cannot translate that into practical change.
creative ideas that are not limited by current thinking or beliefs
Wiktionary defines it as:
blue-sky thinking (uncountable)
I'm wondering how this phrase originated.