I decided several months ago to turn off the Outlook desktop alert feature, and I'm glad I did. In Outlook 2003, the alerts pop up in the lower right-hand side of the screen each time an email arrives in your inbox, which for me was just about every 2 minutes. The brief interruption inevitably messed with my train of thought.
If you're a frequent user of web conferencing software, beware of the Outlook alert. I've been a participant in several web conferences lately where the presentation has been interrupted by an Outlook alert on the presenter's desktop, displaying text from a message that the the presenter would have most likely preferred to keep to him/herself. I won't name any names, but I've personally seen this happen twice in the last week.
You can be forgiven if you don't know how to turn off this email alert feature, which is turned on by default in Outlook 2003, as it's quite buried in the Outlook menus. Select "Tools - Options", then click on "Email Options", then "Advanced Options." and remove the checkmark next to "Display a New Desktop Alert."
So be kind to those who are sending you what they expect are private emails, and either exit out of Outlook before hosting a web conference, or turn the darn thing off forever.