The Original Stretch-Text
While Friesner's original code works just fine, my major complaint with it was that it required explanation. Unless you knew to click on the bold text, you might miss it. The explanatory text is fine, but navigation, to me, should be more intuitive.
If the goal is to make a "standard" for stretch-text use, the fight is lost before it's begun; beyond some very basic web standards, individualization rules the internet. Although referred to as a "standard", the policy of underlining or blue-coloring hyperlinks is entirely style-dependant, as the "no link" stylesheet on this site proves. Of course, simply maintaining consistent form yourself throughout a site can go a long way; even if it is harder to figure out what to do, once a precedent has been established users should rapidly adapt. For that reason, a basic format should be followed with regards to the <span> tags that are used.
In the meantime, if you absolutely have to use stretchtext, go ahead. It's not a capital offense to use invalid HTML, I just do not wish to include a tutorial on how to do so within a site at least partially dedicated to the notion of web standards. Try altering the CSS to better integrate the text with its surrounding material: perhaps try coloring and styling it like a different form of hyperlink to indicate to people that it is clickable. Also investigate use of "cursor: pointer" commands to draw focus. Dev Guru has a nice CSS2 index for reference.