.odt or .doc?
It is a fact that Microsoft Office is more popular than any other office suite there is. Corollary to that fact is a sad reality: That Microsoft Office is a proprietary, vendor-lock-in software that goes against the grain of free and open source software (FOSS) advocacy.
So, are there workarounds for us OpenOffice users? How do we deal with our friends, future employers, partners, etc. using Microsoft Office, who will get miffed receiving .odt, .odp, and .ods files? To please them, we would save, if not convert, our OpenOffice files under Microsoft Office formats. This is tedious and "anti-FOSS", though.
If OpenOffice can nowadays open even the .docx formats, why can't Microsoft Office open the ODF formats in return? Good news is that there's already a plug-in for Microsoft Office by which ODF files can be converted to proprietary formats of Microsoft Office.
The answer to the question, therefore, is: Do not share .doc formats. Share ODF, PDF, RTF, plain text files, or even HTML files, depending on level of complexity of the files you're sharing.
You may add a signature to your emails, which contains an advice that your recipient/s should try OpenOffice.org, a free and open source office suite. The advice should also include a link to the ODF plugin.