The bruhaha over the HTML5 Logo [w3.org] is/was somewhat of a hornets nest (I don't like the CSS3 icon in "related technolgies" bit, either ;)) but reading the outcry after the event helped explain (to me anyhow) how the W3C position over the "5" differs from WHATWG - @Robert Charlton: not sure if that's what you were referring to with your "civil war", perhaps it was just the military style of the logo hehe but I was initially confused too.
The WHATWG is the group who are dropping the "5" as they will always be working on and promoting HTML as it evolves, this makes sense for it to become a Living Standard [whatwg.org].. the W3C are going to take "snapshots" at points in the development, maybe that's so the browsers can 'officially' benchmark against something, or validators have something to validate to. These snapshots will still be released under the HTML5 "set of technolgies"; toungue in cheek reference to their earlier faux pas whereby they inferred HTML5 actually encompassed CSS, SVG, WOFF etc. - Under that shiny new logo, which may not even be final yet, authors are encourage to bend/shape it any way they like. Which is to say it will be likely the more implemented and tested parts of the living standard which would get included in the W3C snapshots, it will not, and shouldn't, stop browsers using the WHATWG standards to introduce these features so they can be used and tested.
The Logo is to be credited to the W3C and Tantek's suggestion about how to reword some of the FAQ has been listened to and they've changed already. It originally sounded like (some say the military style badges) suggest HTML5 is the 'be all and end all', when in reality it's only the cornerstone that all these other, separate, technologies are related to.
>>re: faux pas it has now been corrected, and it was kinda like the next part of this reply - CSS3 is not part of HTML5, so CSS discussion in this thread is probably OT :o
.. hopefully not as a x-browser rec though. Browser specific applications maybe, or some sort of preprocessor/API - @kaled, CSS Variables & related [webmasterworld.com]. post #2 leads to an older thread where it was discussed as it pertains to the CSS specs. The technology to do this already exists.</OT>