I couldn't find any way in the spec to put in a "hard space" which would not removed. E.g {{{"|Row one"}}} vs. {{{"| Row one"}}}

-- [[Isonomia]] 2008, Apr, 28

There isn't.

-- [[YvesPiguet]], 2008-Apr-28

Logically speaking a "hard space" ({{{ }}}) should be an escaped white space {{{"~ "}}}. Obviously this may not be isn't possible which makes a space a bit of a special case alongside a "hard newline" ({{{<br>}}}) which should be:-

{{{"This is a line of text~<uline>

OK, so it would appear that a "hard newline" is \\<uline>

Accoding to wikipedia " In Wikitext, the character entity reference   often represents NBSP.
 In TeX and LaTeX, a tilde (~) is used to denote the hard space."

Assomeone who can't remember   even though I use it regularly I wouldwholeheartedly try to disuade anyone from using &nbsp. ~ would be asensible proposal, but 10:1 people will not expect ~ to suddenlydisappear everytime they put it into the text so I wouldn't support itsuse.

Other suggestions I have are:-

# {{{ {} }}}  "An empty image????"
# {{{ <> }}}  "???
# {{{ [] }}}  "An empty link .... I'm going to suggest this for internal links"
# {{{ \~ }}}  "Almost logical but Not at all practical.

Ican't remember ever seeing "<>" being used elsewhere so perhapsas it almost represents a container of space, it is perhaps the mostsensible proposal.

-- [[Isonomia]] 2008-Apr-28