Moved from another thread:
Right-click the labels for the position fields in the edit window and a pop-up menu comes up with Copy and Paste. What it copies is the vector with all three position values in it. You can paste it into a script, notecard, or chat (as "<12,34,56>" for example) or right-click another object's labels and paste all three values at once.
Do the same for Size and Rotation.
Copying a vector or rotation from some text source would also let you paste it, translating between rotations and vectors as needed for the rotation fields.
For extra credit, add a Copy All and Paste All to each that will copy ALL of the fields at once, except position.
For EXTRA extra credit, parse the Copy All data into the clipboard in a format suitable for pasting into a llSetPrimitiveParams function. (And the opposite for pasting.)