I admit to wondering about the posting-on-AO3 thing, too (and the tag-wrangling wackiness involving that other Holmes-in-the-future story initially confused matters even further -- if sanguinity didn't do mine, I think there's a chance she might have done that one).

In any case, I think there's definitely misdirection going on in that comment thread. If she didn't write "Echoes", I'd lay dollars to the proverbial doughnuts that she was its beta.