Hi Bright,
Also, when you say 'everyone', do you mean the everyone including guest from your site? If yes, then you will need to configure your privacy the System -> Other items to 'everyone'. Please see
http://screencast.com/t/Uyqwlp7Z
Currently EasyDiscuss items the privacy is using this rule so setting this rule to 'everyone' will allow your site visitor to be able to view your ED stream items
Hope this help and have a nice day