Just discovered this: a DIY marker database. Seems to operate on a Wiki model.
There must be some system to composing text for plaques; most of the ACW ones seem impossibly verbose.
My model marker would read "George Washington slept here en route to Valley Forge." Everyone knows Washington and Valley Forge. This marker would tell who, what, where in a short sentence. Many of these ACW markers, on the other hand, seem to be trying to educate the reader on multiple points of history; some read like excerpts from textbooks; some even give background information.
The trend, as with advertising in the 1960s, is clearly towards long copy.