To monitor offensive content, you can set content controls within the browser's preferences. The following instructions are for most common browsers:
For Internet Explorer 6
Go to Tools -> Internet Options and select the Content tab. Under the Content Advisor, click Enable to access the content settings. By selecting the Ratings tab, you can specify the tolerance level for each topic by moving the slider between 0 to 4. The Approved Sites menu allows you to designate permissions for sites by choosing Always or Never options. To protect your settings from being modified by other users, set a Supervisor Password under the General tab. Select Apply to activate the new settings.
This browser does not come with built-in parental controls, but you can download content filter extensions through Mozilla's web site.
Go to OS X System Preferences -> Accounts. Select the user account and Parental Control button. From this menu, check the Safari application and click on Configure to edit the browser settings. The prompt will instruct you to open Safari and enter allowed sites in the Bookmarks window. Your Administrator's password is needed to edit the Bookmarks or add a new site.
For more information on Internet content rating, go to http://www.icra.org