I hope this is enough of an actual data point to justify posting it...

I've only seen people using external strategies. The colorForth folks
all seem to keep a stack of floppies. And when I was messing around
with herkforth with Jason Woofenden, he had it set up to keep a series
of image files (or to increment the "zero" block in the native version).
You mostly just backed up to the most recent one when he had screwed up
his current image, and occasionally one farther back to revert from a
failed experimental branch. And when you were pretty sure you were in a
stable state, you'd move your current copy back to the begining
(destroying all the history). I don't recall that we did much code
sharing, though I have a vague recollection of putting one of his images
in one of my history slots and copying some bits and pieces over.

Gah. It's so tempting to speculate; version control is such a
fascinating topic...you might have to start a new thread to try and draw
off some of the inevitable noise. :)

--Josh