I've read in the "About Service Pack 2 for SharePoint Products and Technologies" paper that SP2 includes an update for the Update Statistics Timer Job that causes SharePoint to run SQL Server's online index rebuild feature (p.4).
I'm uncertain of the terminology here but is this the rebuild that SQL Server uses for minor fragmentation (up to around 40%) and leaves the DB online? I'm also guessing that this will therefore not rebuild severely fragmented indexes as I think this requires the DB to come offline. Can someone please confirm my belief here?