Youtube seems to have a different interface for sharing a channel, a playlist or an individual song. Also it seems to be missing out on revenue from Itunes (or maybe it isnt). and it seems to promoting Facebook and Twitter to the expense of other social media sharing buttons which can be only seen when you click share more (or maybe the buttons/social media channels change based on sharing activity analytics 🙂 )

on a slightly different note read my techie tutorial on boosting your youtube channel views

https://decisionstats.com/2010/09/10/creating-an-anonymous-bot/