Answer: Google Video. In an e-mail from Google to users, the company announced "Later this month, hosted video content on Google Video will no longer be available for playback. Google Video stopped taking uploads in May 2009 and now we're removing the remaining hosted content."
Since Google purchased YouTube in 2006, Google Video has withered. If you have uploaded video to Google Video, you have until May 13 to download it back. Here is a link to a copy of the e-mail announcing the service shutdown: http://www.deaddyingdamned.com/assets/Google_Video_Shutdown_Email.html