Podcasting Relationship to Social Media

This blog post from Social Media Today, brought up an interesting topic: Is podcasting considered a part of social media? The authors response was no, and that the distinction for podcasting was that it is a form of new media and not social media. He cited his reasons as that this medium is considered to be a one way dialog and to qualify as social media there needs to be more than one person engaging in conversation. This then begs the question of what is social media then. According to Wikipedia the definition is:
'the use of electronic and Internet tools for the purpose of sharing and discussing information and experiences with other human beings.'
What do you consider to be social media? Do you disagree with the author on his stance on podcasting and its relationship to social media vs. new media?