Yet another Update
So, they are calling it “CommonMark”. Not quite as catchy, but who cares. As long as it's technically sound.
Update
Seems like the “Standard Markdown” effort didn't really look at John Gruber's licencing text, that he used for the original description. It allows you to do just about anything you like, but one of the few restrictions the licence includes is that you cannot use the name “Markdown” or the name of any of the original contributors to endorse or promote derived products. At least not without specific prior written permission. So now Gruber is a wee bit pissed, and understandably so, if you ask me.
Yet, having a specification of a language that is used for input into computer programs, that is not ambiguous sounds like a good thing to have. I don't care about what they will call it (I don't know if the panic move to “Common Markdown” makes any sense, since “Common” is pretty much a synonym to “Standard”), but from a technical point of view it is a move in the right direction. If you cannot find agreement, find another clever name and run with that.
Markdown is great. Usual texts are simple, and you get away with minimal markup languages such as this. If you want to do stuff like control text colour for individual words in a document, you should see a doctor anyway. If you'e a reasonable person, markdown is what you are looking for. This blog (and indeed the rest of my website) is also written using markdown, processed by ikiwiki.
Jeff Atwood just blogged about Standard Markdown, which came to be because the original Markdown description by John Gruber isn't an unambiguous specification. That's where the spec of the Standard Markdown comes into play. Sounds great.
The one concern I had was, whether or not this project had John MacFarlane on board. My concern was unfounded, because John is in. Knee deep, as it would seem: He wrote the specification as well as the standard implementations in C and JavaScript. ☺
Why I am such a fanboy? Well, basically because John is the author of pandoc, the most awesome document processing tool you will ever come across. It can - brace yourself - convert Markdown, reStructuredText, Textile, HTML, DocBook, LaTeX, MediaWiki markup, OPML, Emacs Org-Mode, txt2tags, Microsoft Word docx, EPUB, or Haddock markup to - sure, take a moment to catch your breath - HTML (including HTML5 and shiny things like slideshows using reveal.js and stuff like that), EPUB, FictionBook2, Microsoft Word docx, OpenOffice/LibreOffice ODT, OpenDocument XML, DocBook, GNU TexInfo, Groff man pages, Haddock markup, ICML a markup language used in Adobe InDesign, OPML, LaTeX, ConTeXt, LaTeX Beamer slides, PDF via LaTeX, Markdown, reStructuredText, AsciiDoc, MediaWiki markup, DokuWiki markup, Emacs Org-Mode and Textile. It is positively mind-boggling. The project's website features a diagram, that visualises this paragraph, if you can't believe it…
Write your documents using pandoc's extended markdown, keep them in version control (because markdown is a plain-text format, that's trivial), and generate whatever format you need. Seriously, if you're still using “office” style programs to write your documents with, you can't be helped.
I'll acknowlegde, that sometimes you'll want full control of your document, and sure, use LaTeX in those cases. But the newest pandoc has support for calling filters during the conversion phase, which open the door for almost any extension you can think of. I'll use markdown&pandoc for the next larger document I have to write. I did use pandoc to produce my latest presentation slides: The filters feature of pandoc allowed me to extend pandoc's markdown to target multi-column slides as well as freely positionable images. It produces LaTeX beamer slides in PDF format, which are plain beautiful anyway.
Pandoc has installers for windows and OSX, too. So there's no way you'll get away claiming it's not available for your platform. Your linux installation will probably feature pandoc packages out of the box; if not: Switch to debian already! PDF output needs a LaTeX installation, but there are open-source distributions for all major OSs readily available for installation.