I created a plugin that automatically updates your YouTube links throughout your WordPress site (and YouTube embed codes) to use YTkeeper.com and direct to any known working videos if the original links ever get taken down. It checks and corrects content output from pages and posts to use the service. For all other general needs, you can still manually replace youtube.com (or youtu.be) in your links with ytkeeper.com to keep them working.

Download: ytkeeper-0.1