A quick google shows some results which look like pet projects of small business which have obviously failed (since I've never heard of them before)
All of these new document formats that are pushed by big companies (some are really great I actually love using Google Docs) try to tie the user as close to their eco-system as possible.
When ever I try to maintain documents for long term storage, markdown seems like the only good format. I've seen people talk about stuff like org-mode, etc, but they all lack the fluidity and the WYSIWYG nature of Google docs, docx etc. I'm talking about how markdown never actually stores pictures inside the document, but just links to them, and you'll have to use a specific application to view the rendered markdown, and a different one to edit or make new ones.
I'm interested to see that does everyone else use for documents? And please don't suggest docx+open/libre office. I'm still waiting for some of those applications to properly handle a big file and I don't want to wait so long for those applications to even open.
EDIT: Thanks for the replies. I think I should clarify something. I'm looking for a WYSISWYG tool, like google docs/docx. I don't really have time to spend doing the edit->render->see where you went wrong->edit cycle. This really hurts productivity when you're editing large documents and increases the barrier for new comers. I do use LaTeX but only when I need ultra sharp looking documents with specific needs. I really like it, but only pull it out when I need to write a paper and want the output in PDF. Other times, it's really not worth the effort.
So formats which require me to render to HTML etc, are a no go. I'm looking into ASCIIDOC but even that looks like it's very similar to markdown. And by WYSISWYG, I mean I want to type, and press Ctrl+B to write in bold, and Ctrl+I for italic and right click to insert hyperlink and so on. Not use asterisks everytime whenever I want to make something bold. Sure it transparently to that in the background, but I shouldn't have to worry about it.