In the case of Invisible Content Just for Screen Reader Users, a WebAIM article concludes this:

[...] the CSS techniques presented here are used to hide content, sighted users will never know that the content is there at all (unless they disable styles). Screen reader users, on the other hand, will never realize that this content is invisible to sighted users.
The part where screen reader users are unaware that the hidden content is for them, obviously, made me wonder if there is a way to clarify that for them: what content has been added on their behalf.

For one thing, for them to be able to properly evaluate how much better is it and to be able to provide valuable feedback.

The solution has to be simple enough to accommodate older agents as well.

I thought about using elements like <strong>. It's won't be very obvious, but it will be a pattern on a site a screen reader user should be able to easily id, since it won't make much sense.


To exemplify.

The WebAIM breadcrumb:

Code:
<p id="breadcrumbs">
  <span class="hidden">You are here: </span>
  <a href="/">Home</a> &gt; <a href="/articles/">Articles</a> &gt; CSS in Action: Invisible Content Just for Screen Reader Users
</p>
The "hinted" WebAIM breadcrumb:

Code:
<p id="breadcrumbs">
  <strong class="hidden">You are here: </strong>
  <a href="/">Home</a> &gt; <a href="/articles/">Articles</a> &gt; CSS in Action: Invisible Content Just for Screen Reader Users
</p>
Normally, it doesn't make a lot of sense to use strong there. This odd event, of using a strong element when there is no "ominous" context, can it became a pattern screen reader users would recognize somehow?