It's interesting to match our communications needs to the right channel. We have an overwhelming choice when it comes to how to reach our fellow humans:
- Talk to someone
- And others
Different mechanisms have different priorities and groups. We fit the urgency, size, privacy, interactivity, audience and importance of our message to the right channel.
Google+ seems like the right format and speed for quick comments on technical things. Twitter is great for thought bites, many of which turn out to be either complaints or discoveries. Facebook is about family and friends.
This means that we don't have a hierarchy of channels, but a graph. And I don't see there being winners or losers. I don't mean the deluge of identical startups rushing to do something social that's been tried before and doesn't work (eg finding nearby contacts or uploading and sharing photos), I mean the core backbone services. They are probably fixed for a while anyway.