When you send an email to multiple people, those people can see who else got that email. But if you don't want certain email addresses to be visible to others, this is how you do it in Outlook 2010 in secrecy.
If you use Google services such as Google Reader, Google Drive, YouTube, Contacts, Google+ Circles, Latitude, Picasa Web Albums and a few more, you can download all of your stuff to your computer.