eBay has gone from anonymizing bidders when the bidding reaches $200 to anonymizing all bidders. Here's their notice (I first noticed this March 6, 2008):

      To help keep the eBay community safe, enhance bidder privacy, and protect 
   our members from fraudulent emails, eBay has changed how User IDs display on 
   the bid history page. Only you and the seller of the item can view your 
   User ID, all other members will see anonymous user IDs, such as x***y.

All the timing information is preserved, however.