What Would A Galactic/Intergalactic Civilization Look Like?

  Even if they come in peace human history shows that interactions between different cultures even if no hostility is intended, can have devastating effects.

  One of the things I was thinking about earlier is that assuming contact is made by ships say away from settled areas then both sides are likely to be very reluctant to give away any information about themselves and their origins for fear of exposing them to potential attack.  In fact there was quite a good short story about this.  Can't remember the name/author but after a lot of nervous maneuvering both sides come up with the same idea to avoid having to fight.  That they swap ships and each take the other's back home.  Of course a fair amount of problems with this idea in reality.