I seem to be miscommunicating. I'll try to clear things up.
If I have two seperate computers each with an installation of Eagle, then I have two seperate library directories stored locally on each computer. If I change a library on one computer, the modified library does not automatically show up on the other computer unles I manually copy the .lbr file from the first computer to the second computer.
That is the pain in the butt I'm talking about. Unless you have your library directory on a network drive, you have to copy over the .lbr file (thumb drive, CD, email, 5¼" floppy, punch card, whatever) manually. If you only do this every once in a while it's not that big a deal but if you modify libraries often, it can become tedious.
By running my Eagle off of a thumb drive, the entire directory structure (including the library folder) is stored on the thumb drive so no matter what computer I'm on, I have the latest versions of all my libraries.
I hope that made sense
Exactly!