Useful as it is, StretchText is surprisingly unpopular. At the time of this writing, the English language Wikipedia entry for StretchText devotes fewer than two hundred words to explaining what it is, which is basically this:
That bit of stretchtext» above is at the heart of the zombie bibliography I began last year. On that page, stretchtext's ability to facilitate information discovery without disrupting orientation is apparent.
Stretchtext has the ability to introduce supplemental information to readers while enabling them to hold their places, an important feature for text that requires long attention spans. But if stretchtext is potentially useful for electronic academic reading, one of the things delaying/preventing its adoption may be the aggressively homely and obstinately idiosyncratic implementations of stretchtext.»
My own implementations are imperfect at best, and my designerly execution leaves much room for improvement, I know. But I do think I nailed the horizontal animated, sliding, collapsible <span> using Javascript and CSS.» Check the second sentence of the second paragraph of my most recent blog entry for one fun stretchtext example.