Inside AdSense Team Message:

As you may know, we frequently review our products and features to ensure their effectiveness. After reviewing our AdSense video units feature, which allows you to show YouTube content and ads on your pages, we’ve found that it hasn’t had the impact we had hoped for.  As a result, we’ve decided to retire this feature at the end of April so we can focus our resources on other opportunities to help publishers earn from their sites.
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Once video units are retired at the end of April, any remaining Leaderboard or Skyscraper video units on your pages will direct users to YouTube.com, while other video unit sizes will automatically be changed to standard embedded YouTube players.  These standard video players will display top YouTube videos, but you won’t generate earnings from them once this change occurs.

Source: http://groups.google.com/group/Inside-AdSense…