Re: proposal: subline element

I've read through the other comments and one theme I'm strongly opposed to
is that of making <subline> a child element that can appear _inside_ a
heading. Validators should read "you can't use a <subline> in this context".

A subheading is not a component of a heading but a complement to it. To
take a random (and rather dry!) example I found (here:
http://dalicetrost.com/wp-content/uploads/2012/08/Proposal-cover-graphic.jpg).
..

Proposal For In-house Training Services
Transformational Communication Skills

<h1>Proposal For In-house Training Services</h1>
<subline>Transformational Communication Skills</subline>

Note that both the heading and subheading are on separate lines (the clue
is in the elem name "subline") and consist of separate phrases. In my
experience, this is the convention (see also the Dr. Strangelove example).
If it should appear underneath (sub!) make it block level! I understand
that this is the intention already, but I think making it a sibling (not a
child) in authorship advice is important to avoid things like...

<h1>Proposal For In-house <subline>Training Services</subline></h1>

"Training services" does not represent a subheading but a fragment of the
heading; a part of a complete phrase. Here, a <span> or <em> would be
better (and is already a popular choice for keyphrase differentiation and
styling).

Cheers - Heydon.