"found that the lack of a powerful e-mail application could hinder the adoption of Linux on the desktop. "
Hmm, don't know what they are talking about. I've used Outlook, Outlook Express and Thunderbird. As an e-mail client, Thunderbird beats the stuffings out of the other two. If the scheduling functions of Outlook are desired, then add Sunbird. That combo is much more powerful than Outlook.
Ok, that is in the article. Personally, I don't have a need to integrate the two, but they apparently plan to do that.