Answer:
Passed from father to son and shared between brothers, its importance is unquestioned though it is used more by others.
Sometimes you feel it weigh a ton. Yet it is nothing, but somehow still there. Makes you uncomfortable around anyone, But speak its name and it's gone.
Sends paper without using the post office.
Timid or weak people are said to not have these.
What heavy seven letter word can you take two away from and be left with eight?
I am the fountain from which no one can drink. For many I am considered a necessary link. Like gold to all I am sought for, but my continued death brings wealth for all to want more.