The original question:
I'm in a group where everyone is using a different format for exchanging documents. Currently I've seen doc, docx, odt and pdf. The author uses what they know / like and is amazed that others can't open the document. I think everyone is using Windows though an Apple user is possible and I doubt there are any Linux users.
Here is part of the answer. The technical answer.
Everyone should use DOC (not DOCX) format for exchanging files to be edited. It has become virtually a standard for the last 5-10 years. Almost any word processing program, including open source and Apple ones, can open, view and edit DOC files. It's just that simple and I don't get why a bunch of techies can't agree that this is one de facto standard that all businesses use.
Forget (please) PDF for the purpose of editable documents. Nobody uses PDF for this purpose, even if Open Office can do this.
But do use PDF for any and all non editable "display only" documents because it always captures the physical appearance of a printed page. A PDF is what you send the printer. A PDF is NOT!!! dammit what you send a team member who needs to add to your work.
ODT is questionable because the non Open Office users will have their little open source specific brains explode. Word 2003 (I checked) does not support it. Dunno about later versions (it was the last decent version without the ribbon bar.)
HTML - a really bad idea. Don't use that for editing documents, and don't use it for sending display only documents. It simply does not have the same characteristics for editing and layout as Word or any other word processing application, and HTML rendering still varies a little.
You knew all this already, right?
Now the human part. A bunch of volunteers sounds like nobody will pay attention to or understand a standard. Some will view it as a dictatorial limitation on their freedom.
Example interaction: "Why cant' I use DOCX? It's (duh duh duh) BETTER than DOC, right? Oh, and duh."
If you want to take control of this irritating problem, then circulate a memo where you explain exactly what the standard should be and why. And cover the most likely end user miscomprehensions and "getting creative"sideshows. Especially tell them why the default file type that the stupid word processing program wants to write out won't be editable by some others on the team.