Outlook Express has a feature that allows you to add addresses you reply to, to your address book. Many users who move to Outlook miss that feature. I'm not sure why, it tends to fill your address book up really fast, especially if you are active on mailing lists… But many people like the feature and miss it.
Outlook 98/2000 in Internet only mode offers the ability to automatically add addresses to your Contacts folder. Anyone using Corporate mode or Outlook 2002/2003/2007 needs to add the addresses to contacts themselves. It's not hard – right click on the From field (or To/CC fields when other addresses are included) and choose Add to Outlook Contacts. This works with an open message or from the preview pane, in all versions of Outlook.
Unfortunately, when messages are sent to more than one person, you can't right click and add everyone to a distribution list. You'll need to do it one address at a time, first add to contacts then add to the distribution list.
Update: Outlook 2010 adds address you send email to, to the Suggested Contacts folder if they are not in your Contacts. This avoid filling your main contacts folder with junk but saves them, just in case you need them later.
Published July 25, 2003. Last updated on September 12, 2013.