My bad, I see where I went wrong. I originally made the example functional, but none of that went through the submission, so I had to yank it out but I forgot to put the exampled bits back into words.

Anyways, I meant for this to be an addition to the tagging system, not a whole brand new thing. So to include an entry in the series you'd just give it a tag like usual, to insert an entry in the middle of the series just make sure the date on the new enty placed it where you wanted.

Basically, the <series> tag would embed a specialized view of the tag page into the entry.