They went to a poetry reading, but they got bored and restless. As far as they were concerned, it was for the birds. They left.
As far as I am concerned, the expression really means “based on my knowledge”, but in the sentence above it does not seem to mean this, does it?
I’m also wondering if this expression is used when not talking about humans. I have heard things like “as far as their economy is concerned” and so forth.