You can change the visibility options related to Support Center and Knowledge Base on what information to be shown to your customers.
To check out these options go to Manage --> Account Settings --> Support Center Settings and navigate to the last option Visibility Preferences:
1. "Allow customers to view KB without logging in" check box will let all Support Center visitors to access your KB articles without requiring to login.
2. "Allow customers to view forum without logging in" check box will let all Support Center visitors to access your Forum without requiring to login.
3. "Display forum guidelines for new posts and replies" check box will display the guidelines to end users who create new posts. The guidelines will show on a separate section within the Post.
4. "Display request new account button on login page" checkbox will enable an option for end users to request for a login account.
5. "Display submit ticket options in support center" checkbox will enable Submit Ticket link at the top of the Support Center
6. "Display login link in support center" checkbox will enable Login link at the top of the Support Center
7. "Display captcha for end user forms" checkbox will force your end users to fill the captcha field in all the forms.
8. "Allow clients to login via Google+" checkbox will enable an option for end-users to login to Support Center using their Google+ ID.
9. "Show category prefix in Ticket Creation forms" checkbox will display the category prefix you have set up, in new ticket forms.