Triple tags 

I've updated a broken link in this section.  However, as far as I can tell, none of the links demonstrate the history of triple tags as described in this section - they don't disprove it either, they're just several isolated posts talking about tags of a similar form, making no reference to one another.  There's no news-style discussion of "wider acceptance" or the development of the format.  It's all primary sources, which is a bit awkward.