It's a useful concept, but I have doubts about its sticking, if only because it sounds too much like 'equal'. Plus we already have side-story, which pretty much does the job.
Here's the link.
Having enjoyed the GOLDEN COMPASS movie and been disappointed that naysayers helped stop the second and third films in the series from being made, I was glad to hear that a tv miniseries is currently in the works from the BBC. Let's hope it's a similar quality and fares better.
current reading: IN THE REALMS OF MYSTERY AND WONDER (Clark Ashton Smith artbook).