More info
Switched browsers in the continuing struggle to figure it out...
I'm using Mary Anne's "Decoration Day" post in Community as my benchmark. I happen to know she composes offline in Word, and am certain that she has "smart quotes" turned on.
The quotes, apostrophes and dashes in her post all display properly when viewed with IE. In FF, they're replaced with a circumflexed lower-case 'a' and two question marks.
IE comes with the default encoding setting of "Western European (Windows)". But resetting FF to the same encoding does not clear up the display problem.
Still working on it...