whitaker just finished a huge honkin' patch which completes the memcaching of the friends pages. (woohoo!)Previously we were only memcaching clustered stuff (loading people's entries), but Whitaker added support to memcache everything, including all the global (non-clustered) queries, like finding a user's friends and colors, finding when they last updated, etc.
If you know Perl and got a few minutes, please review:
http://www.livejournal.com/community/changelog/944019.html
Also, warning: this is the first patch where we've been unable to keep the non-memcached version as fast as before. (Well, we could've, but it would've involved massively parallel codepaths, one of which would've bitrot.) So if you're running a loaded LiveJournal-based site and plan to upgrade to this code, be sure you're using memcached.
Whitaker and I have spent quite some time reviewing this, and Whitaker's done a bunch of testing, but it won't go live for a number of days, probably. When it does, though, we expect some impressive performance improvements.