The largest change has been the introduction of a caching daemon - memcache - that has been showing remarkable success in hit rates, significantly lessening the load on the database servers.
However, as it is new, we have been working out some bugs that have resulted in some downtime.
As we continue to work on this, as well as other hardware upgrades and more database moves, we feel confident the site will be much faster and more reliable.
There may continue to be times outside of the maintenance window where the site is slower than normal or unresponsive as we perform the upgrades. We will update here and/or at status.livejournal.org as we can.
We really want to thank all of you for your past and continued patience.