If you have an Email service provider or agency doing your email marketing, you should ask when they will start supporting this new Email reader which will grow steadily in importance as more corporates install the new Microsoft Office (always a slow process) and users get it bundled on new PCS - so no real panic - will take a while to grow, so only really an issue for high email volume broadcasters.

If you manage your own e-mail marketing or are an agency, then see the two links below.

Why have these changes been made?

In the new Office 2007 release, Outlook uses the HTML rendering engine from Word 2007, not related to Internet Explorer or the operating system. This is probably for anti-trust reasons - to reduce the dependence between the applications and operating system.

What changes are introduced by E-mail rendering in Outlook 2007?

These are dramatic if you believe this widely referenced post summarising email rendering differences in Outlook 2007. However, this is scare-mongering to an extent since you will only have big problems if you use external CSS stylesheets which is not common practice to avoid problems with other email readers. However, you may have problems with inline CSS and background colours and images, so its a must to test for.

For the definitive low-down on rendering capabilities, read this post from Microsoft:

• Word 2007 HTML and CSS Rendering Capabilities in Outlook 2007 (Part 1 of 2) - this contains a full listing of supported and unsupported capabilities and also includes instructions on downloading a validator to check your email HTML/inline CSS code.