If you are user of the excellent XMPP service at jabber.org you may be interested in this announcement - you should also receive it directly to your JID from Peter Saint-Andre - our precious master of puppets:
We will make a copy of the data for all 330,000 users on Saturday morning, complete data migration over the weekend, and then switch to the new software Monday morning (European time). Once we copy the data, any changes you make (e.g., adding new buddies to your contact list) will be lost, until the new software is installed and running on Monday.
Fingers crossed for the successful migration.