The Bristol Blogs network uses a plugin called Akismet to moderate external comments on blogs. If you have enabled a comments feed this will protect it from spam and offensive language. Further information about how this plugin works can be found on the Edublogs support site.
Activating Akismet
The Akismet plugin is installed at a network level so there is no need to install it on an individual blog.
The Akismet settings can be found by navigating to Dashboard > Settings > Akismet. These settings will only appear if the site is publicly visible. To change your visibility settings, navigate to Dashboard > Settings > Reading.