The speaker says that the internet is the first medium in history that has native support for groups and conversations at the same time. what does he mean by this ? illustrate with an example? ?

The speaker basically means that, in the 20th century, the media landscape was focused more on one asymmetry than the other. The media that was good at creating conversations was not good at creating groups and vice versa. However, this changed with the introduction to the internet. The internet has both of these asymmetries at the same time. The internet gives us the many-to many patterns as compared to the case of phones that gave a one-to-one pattern. Internet has enabled groups that either watch or listen to something be able gather around and talk to each other. An example is Skype. With Skype, you can have conversations with family, friends or colleagues and have an online teleconference conversation with a group of  people at the same time.

is this supposed to be a question ?