Quote: scarletMS office is incompatible with itself. If you send a .doc or .pub to someone with a different version, they can't open it.
Sorry, but thats not totally true.
If your working on a new version of office, it can cause problems when other people on older version want to open your documents. But otherwise its generally fine.
THe only one I have ever really seen a massive problem for this is Office 2007.2008 with the new DocX format, a cause of many a support call nightmare when the client refuses to accept changing a drop down in a dialog box as a valid workaround.