Earlier today, I moderated an SIIA panel entitled "Why Twitter Matters".
I was lucky enough to have three great panelists, which made my job really easy:
Philip Pearlman, Director at StockTwits
Jacob Harris, Senior Software Architect, New York Times
Sarah Austin, Real Time Matrix
The event was sold out, but for those who missed it (or who care to re-live it), here's the video
Supporting materials including my Introduction to Twitter deck are available here.