Greiner said he is singling out Outlook because of its No. 1 position in the market. "If Microsoft can shift to a standards-based approach for Outlook 2010, you'll see a lot more pressure on other e-mail clients to follow suit," he wrote yesterday (Australia time).
Kennedy gave no indication that Microsoft would make any changes.
He said Microsoft's determination to use Word is driven by the need to serve Outlook's primary customers: corporate workers.
Using Word to display rich e-mails in Outlook ensures that presentations, tables and charts created in Word by businesspeople will display properly when they are sent to co-workers using Outlook for e-mail, he said.
Designers concerned about ensuring their rich e-mails are displayed properly in Word and Outlook, said Kennedy, can refer guidelines published by Microsoft, Kennedy said.
He said that using Word for HTML is not an issue of Microsoft flouting standards.
"There is no widely-recognized consensus in the industry about what subset of HTML is appropriate for use in e-mail for interoperability," he said.
"The 'Email Standards Project' does not represent a sanctioned standard or an industry consensus in this area. Should such a consensus arise, we will of course work with other e-mail vendors to provide rich support in our products," he said.