FTPOnline.com Tech•Ed: New Dev Tools Leverage Office: "In fact, that major announcement got short shrift in Monday's keynote: now VSTO includes support for building applications inside Outlook. Most information workers spend most of their time inside Outlook – so adding this capability will be a boon to enterprise developers. As Holtgrewe explained, "Technology is not there to keep a geek happy. It's there for the end user. People say they want apps that look like Word, Excel, Outlook – but we say even better to be in Word, Excel, or Outlook." "
Subtly significant -- simplifies creation of many useful app types.