Great presentation but his claims about IM are not solid IMO.

IM is personal messaging i.e. we communicate directly with people in the way that's appropriate. Nothing get's broadcasted out. If anything IM is a perfect list.

I have friends, groups of friends, colleagues, clients etc. on my list but they don't bleed into each other.

Also in most IM you can decide to be invisible for selected people and not for others.