I think this FAQ (http://www.livejournal.com/support/faqbrowse.bml?faqid=50) should be updated to include something like:
The only way to ensure that your entries are not available to the general public is to protect them to be friends only or private: http://www.livejournal.com/support/faqbrowse.bml?faqid=24. If you make sure that none of your public entries contain identifying information about you, you will increase the chances of your journal remaining anonymous.
You also have options to not display your e-mail address and other personal information on your userinfo page. Since some search engines can store this data, you may wish to only display this data to people on your friends list. You can set these options on the editinfo page: http://www.livejournal.com/editinfo.bml.
Just a random idea from wanting to approve someone who referenced that FAQ and wishing they'd include a blurb like the one I mentioned above.