There are a lot of different communication platforms to choose from: email, facebook, twitter. Google Wave is a very promising new unified communication tool that combines all these and more.
What Is Wave?
Google Wave allows people to communicate and collaborate using objects like rich text, photos, videos, maps, and twitter. But also share these conversations with other participants at any point. The new participant can then watch a playback of the history of the communication.
Wave is also live so a person on the receiving end can see letter for letter what is being typed for real-time communication.