Digital Archives and Digital Libraries: same thing?

I'm throwing this little idea out belatedly as I did my first assignment for Digital Libraries on a digtial archive, but I don't see any difference in how a digital archive and library are defined.

I just want to speak quickly in reference to the US digital archive experience. Does a digital archive become a digital library when its purpose becomes access rather than preservation. Its existence brings about a two fold purpose by digitizing materials 1.) there physical access can now be more limited and therefore prolong preservation. 2.) Digitizing opens up a new purpose, an means to allow viewing original materials in almost astronomical amounts. Any one with access to a computer and the internet, now has access to direct viewing of the original constitution, letters between Washington and Jefferson, and vacation photos of the Kennedy’s at Hyannisport.

Just throwing this out. What does any one think about this? Meaningful question or totally pointless?