Simple plugin to keep track of your friends posts, 
similar to the friends page of LiveJournal. Currently you can just add WordPress and LiveJournal feeds.
WORK IN PROGRESS!

WPfriends

Simple plugin to keep track of your friends posts

etspring

NEW: Supports built-in WordPress comments threading! [see notes 2 and 3]
Automatically synchronizes comments from Your LiveJournal blog with Your stand-alone WordPress-based blog.
All imported comments are associated with Your blog entries, crossposted to LiveJournal, and shown along with comments, written in You blog.
You can choose how often do the synchronization.
Synchronization does not slow down loading of Your pages, everything is done in background.
Note 1: This plugin has to be used together with LJXP (LiveJournal CrossPoster) plugin. Support of JournalPress and other crossposters will come in future versions (please feel free to post feature requests at the plugin homepage).
Note 2: Threading depth is limited by WordPress settings (<code>Settings - Discussion</code>).
Note 3: You should consider removing <code>Reply</code> link for imported comments, because they are not really a part of WordPress :).

LJ comments import: reloaded

Automatically synchronizes comments from Your LiveJournal blog with Your stand-alone Wordpress-based blog.

WPfriends vs LJ comments import: reloaded