VI/NROFF symbolics question

[jimi]

In article <319 at iconsys.UUCP>, bryan at iconsys.UUCP (Bryan Cardoza) writes:
> From article <108 at mdiva1.uucp>, by fontana at mdiva1.uucp:
> 
> 	.ds X "A string with a one character identifier.
> 	.ds XY "A string with a two character identifier.
> 
> The leading double-quote is not required, but it increases clarity.
> You would reference the strings as follows:
> 
The leading double quote is required if the string definition
contains an initial blank or quote.

What does it mean to say the "leading double-quote...increases clarity?"
I don't understand.
-- 
Jim Ingram	          uunet!h-three!jimi | jimi%h-three at uunet.uu.net
h-three Systems Corporation   P.O. Box 12557 RTP NC 27709   919 549 8334