It is STRONGLY recommend you put attribute values in quotes in HTML 4.01, although the formal rules allow the omission of the quotes in some ‘rare cases’. In XML and XHTML quotes are always required.
Therefore within HTML 4.01 <br title=FrobozzMagic> would be CORRECT but <br title=Frobozz Magic> INCORRECT obviously within XHTML you MUST quote the attribute value. In other words always use: <abbr title=“Short Sale”>…</abbr> which is the best and safest way.
Well, I really meant the fact that <acronymn> has been dropped in the new version of HTML in favor of this one might prod device makers into accepting that abbr needs to be taken more seriously. I prefer <abbr> purely because it seems more accurate to me (grammatically speaking).
Meh, and they added embed. So those who’ve always used embed, will blindly continue using embed except now it’s legal (if they cared, they wouldn’t have used it in the first place), while the rest of us who never used embed will continue not to do so. I assume the same for abbr (who still isn’t in any vendor’s plan to get some keyboard love). Plus, it doesn’t seem anyone is paying much attention to old tags under the “HTML5” banner anyways. Only the shiny new ones. And then they don’t know how to use them most of the time.