Digg has decided to retire Digg Spy, their live activity feed.
When it was first released, Digg Spy was a nice tool to discover popular content posted on Digg in near real-time. However with time it became less useful, and the only thing it was used for was as a bury tracker.
Digg Spy would be replaced by Big Spy, another AJAX based tool for visualizing Digg activity but it does not report buries.