Writing in the Ancestry.com blog, Jen Hodnett describes a change in Ancestry.com's Tree Viewer. Jen writes:
Last November, we launched a new tree viewer in an optional preview. If you chose to view your tree using the new view, we gave you the opportunity to tell us what you thought of the changes we’ve made. Based on the overwhelmingly positive feedback, we’re turning off the old view and making the new tree viewer a permanent part of our site tonight at 2am MST in conjunction with the scheduled tree maintenance that was blogged about yesterday.
You can read more at http://blogs.ancestry.com/ancestry/2011/01/05/family-trees-new-tree-viewer-launch/