Apache Wave!

DISCONTINUED. READ BELOW. Google Wave was an online communication and collaboration tool that made real-time interactions more seamless -- in one place, you could communicate and collaborate using richly formatted text, photos, videos, maps, and more.

Email and IM are linear contextless communication tools. Messages pile up and get lost or become redundant. There's no way to keep track of who replied to what, or which version of the conversation is the newest. Even if you sort or organize your local copy, no one else benefits from your work.