Privacy for young learners

So, how do we keep middle school age children safe and utilize the power of blogger at the same time?  There are privacy settings in Blogger that allow the student to restrict access to his or her blog to a select group of people.  All of the work that they do will be saved indefinitely and all of the options to create unique and powerful digital artifacts will remain available, however no one will be able to view his or her work unless expressly invited through email.  Invitations can be rescinded as well.