Most of us are aware of “web standards” and its affects on creating “user friendly web based intranet software“, but it is very hard to say the same about the “e-mail standards”. Are the newsletters and announcement mails you send properly displayed on all e-mail clients? If you would like to know about it more, you can visit Email Standards Project website.
You can find very detailed information from Microsoft Outlook to Mozilla Thunderbird, From Google Mail to Yahoo! Mail and other web based e-mail clients. There is also a blog for this project.