As a new feature in TubePress, it is now possible to define whether to start playing the youtube video automatically once the the page is loaded.
This feature will make the task easier for newbies. Sometimes it can be difficult to hit the play button in the embedded video and click somewhere else will send to youtube homepage.
Since every user clicking on the thumbnail image wants to view the video, why not set the movie to autoplay?

Check it out TubePress