May be read only by you. Note that your private entries will also show up on other users' Friends views, but only if they have added you as a Friend and you are logged in and reading their journal. In other words, only you can see your private entry there, no one else can. Your Private entries cannot be read by other LiveJournal users.
May be read only by you. If you are logged in and viewing the friends page of someone who lists you as a friend, you will see your private entries. However, note that only you can view these entries. No one else who views the friends page of your friend will see your private posts. Private entries can only be viewed by the individual who posted them.
I've basically emphasized this fact more, and I've made it a bit more clear by shortening sentences.