I really would like to make a distinction here between source form
documents and final form documents.
I agree that anything placed on the website as a final form document
should be in a generally acceptable "open" form. HTML, Maven Xdoc,
PDF, for example. Word documents are NOT acceptable as final form.
Source form documents are a different issue in my opinion. These should
be in a form that permits straightforward editing. For longer
documents, formats like Word or OpenOffice seem reasonable, since you
need the capability of good editing software to handle these documents.
I don't think that formats like these should be outlawed for source form.
I don't regard Maven xdoc as a good source form for longer documents
since there is no tooling that I have discovered that helps edit them
other than a simple text editor. DITA requires tooling to help - and my
contacts in the IBM ID department indicate that DITA tools are complex
and require education.
HTML is OK-ish as a source form. There are at least some good open
source tools to help edit it. Plain text simply doesn't look good for
longer documents - and loses useful capabilities like hyperlinks.
Yours, Mike.