Originally Posted by Jellby
1. The page templates are specific for Adobe Digital Editions readers, they are not in the ePUB standard (as far as I know), and other readers will probably not support that.
From what I've read so far, that does seem to be the case. It's one of the Adobe-specific extensions that they've added, and it's not in the formal spec at this point. On the surface, it seems like a decent idea since it allows the creator to specify variant layouts depending on screen/viewer size. More of a forward-thinking move on Adobe's part, but it remains to be seen how things play out, and whether it will ever be formally adopted.