It is possible for Paid and Permanent Account holders to add journals from certain other sites to their friends list by using LiveJournal's syndication feature. More information about this can be found at http://www.livejournal.com/support/faqbrowse.bml?faqid=137. Additionally, if a syndicated account has already been created for an off-site journal by a Paid or Permanent Account holder, a Free Account holder can add it to their Friends page, but they cannot create the account themselves.
For journals that are on a LiveJournal-code-based site using the most recent version of the LiveJournal server code, each user's RSS feed is located at a URL of the following form:
Replace www.livejournal.com in the example URL with the URL of the actual LiveJournal-code-based site, and "exampleusername" with the user whose journal you want to watch.
Viewing a syndicated form of a journal in this manner will only allow you to view the user's public entries, even if the user also watches your RSS feed, because you cannot add each other as friends in the way that you can add other users on the same site. Any comments that you leave on the entry through LiveJournal will only appear to users viewing the entry through LiveJournal. As such it is recommended that you visit the other journal site to make any comments.
Because of the recent change of the LiveJournal code that allows the full text of syndicated entries to appear in syndicated feeds, this FAQ needs change. The sentence, "On your friends page, rather than seeing the entries normally, you will see only the subject or first few words of each entry and a link to the entry." in the last paragraph should be
EDITAlso discussed in this post: "a recent version" rather than "the most recent version" and "example.com" instead of "LiveJournal.com"