For the record, it was a power failure at LiveJournal's server co-location facility, Internap that caused the LJ downtime. Complete power failure. Backup power went out. This has happened before (but I'm not sure when).

LJ's machines were with Internap before the Six Apart buyout. They've stayed there. LJ's buying Uninterruptable Power Supplies of their own so that this won't happen again, because Internap's power cannot be trusted fully.

This would have happened regardless of the buyout. The computers have been there at that same company for years. Sheesh, guys.