RE: *scratch* buffer documentation

[Drew Adams]

> How about this addition instead, after the first paragraph:
> 
>   Buffers exist as long as they are used, and are deleted ("killed")
>   when no longer needed, either by you (see Kill Buffer) or by Emacs
>   (e.g., when you exit Emacs, see Exiting).

Minor suggestion (and I agree that it can
help to have some such statement where we
introduce buffers):

"Used" could mislead.  It could give the
impression that a buffer is "no longer
needed" only when it is no longer visible
or is being actively edited by a user.

It's not about whether a user is using the
buffer (or that she thinks she is).

It may not be obvious here that it's about
whether Emacs - anything in Emacs - is
"using" the buffer, i.e., that there is some
reference to it - some need for it.  (But
"reference" might not be clear to some
non-programmers.)

"No longer needed" is probably clear enough,
on its own.  Without saying what that means,
it will likely be interpreted correctly, as
meaning that Emacs (not just a user) needs
the buffer for some reason.

It's OK to be vague about what "need" means,
even if it's not so OK (IMO) to be vague
about what "use" means.  I suggest dropping
mention of being "used".