This question has always intrigued me? In network TV land syndicating shows generally means - making prime time content available to run on other networks (e.g. syndicating Sienfeld).
How does this translate to online video world? Content providers make content available to different distribution channels. E.g. CBS audience network syndicates content to YouTube, Yahoo!, MSN, etc. However, they are generally averse to allow sharing or further syndication to others. Why is that? I believe its the fear of losing ad revenue. CBS does ad-rev share deals with YouTubes of the world, they want to ensure that wherever their content is being distributed, the monetization can be attributed back to CBS.
Here is another data point worth noting - almost 40% of YouTube's stream count are via "embeds" - i.e. shared linked outside of YouTube! In addition, if you pay close attention to ComScore video metrix, you'll note that video stream share is very fragmented - YouTube has the lion share (50%+) but the rest of the share is divided into 100 + players.
Syndication in the online world is very different from TV network land. There are hundreds of viable distribution channels. Content providers have to take advantage of all distribution channels to reap full potential of thier ad revenue.
My assertion is that barrier to universal syndication is the inability to attribute ad revenue back to the content provider. And this barrier is limited by our technical ability to associate ad with the video instead of the syndicated player.
Currently, most video ads are managed by an ad-plugin in the player talking to a video ad server (e.g. Doubleclick or an internal ad server in MSN, Yahoo!, etc). If they could be directly part of the video, the ad revenue could be directly associated with the stream instead of the player. This will incentivize the content providers for universal distribution.