It is possible to enable the autoplay option for Youtube videos in a wordpress.com blog. I used the Gigya method for this workaround.
Code for Youtube autoplay in a wordpress.com blog
[gigya src=”http://www.youtube.com/v/VIDEO-ID-NUMBER” flashvars=”autoplay=1″ type=”application/x-shockwave-flash” width=”425″ height=”350″]
Just change the bit VIDEO-ID-NUMBER in the above code with the actual ID number of your Youtube video.
The detailed instructions on how to enable autoplay are available here
View an example Youtube video that has autoplay option enabled
