It's unlikely I'll make a whole-database search available in the near-term. The entire message table is full-text indexed (took about a week just for that process to finish) and it's slow as molasses. We're talking 30-60 seconds to complete searches and they clobber the server.
So I'll probably only make the most recent 2 million messages searchable initially. And try widening that window until I find the widest window that still allows acceptable (less than 10 seconds) performance.