Can Word open a .odt file?

I don't agree with your advice that the ODT format should not be used any more. ODT is a format that is well supported by Open Office and Libre Office and works very well in my experience. It is unfortunate that Microsoft chooses not to support it, but that isn't a reason not to use it.

ODT is an old format that was replaced by Office Open XML (OOXML). Microsoft switched to OOXML as the default format beginning with office 2007. Apple supports OOXML with TextEdit and has partial support for the current standard in Pages. OpenOffice offers partial support for OOXML, with the latest LibreOffice fork of OpenOffice offering both read and write support for OOXML. No fork of OpenOffice has switched to the current OOXML standard as its default file format. 

Microsoft supports ODT in Office for Windows. That was a result of the timing of the new standard. Years ago Microsoft had been under fire for not supporting open file formats. So Microsoft built in support for ODT expecting ODT to be adopted as the open file standard. The standards body picked a better open format OOXML. The development cycle of Office 2008 for Mac was just beginning so Microsoft skipped ODT support in Office for Mac and went forward with the new standard - OOXML - as supporting a newly discontinued standard seemed kinda dumb,

People resist change. There are billions of files in old prioprietary Office formats as well as ODT that people have yet to convert to OOXML. So far, these old formats are hanging on, much as RTF in its various incantations hangs around.

I stand by my advice to stick with the current standard, which is OOXML. Files saved in OOXML can be opened and used by every word processor I can think of. Compatibility problems are minimized.

I cannot agree to this comment.

ODF is a well-documented, ISO certified, open format. OOXML is *not*. For example OOXML allows the embedding of proprietary binaries (which is of course heavily used by MS products).

There have been many debates about how OOXML could have become an ISO standard at all...

I'm sorry, Stephen, but the facts are: "The [OOXML] format was initially standardised by Ecma (as ECMA-376) and, in later versions, by ISO and IEC (as ISO/IEC 29500)."

- http://en.wikipedia.org/wiki/OOXML

Since this question was first posed, LibreOffice version 4 has been released. This newer version of LibreOffice has better support for OOXML than version 3, but LibreOffice still doesn't default to the standard OOXML open standard and hangs onto the obsolete ODF format for reliability purposes. Converting core OpenOffice code to work with the new file standard is a gargantuan task that has yet to be implmented by open source advocates. On the plus side, retaining the old code base gives LibreOffice the ability to open files that were saved in file formats Microsoft has abandonded and save them in the up to date OOXML file format.