"Incoming message from starfleet command..." because in the future we'll *all* use video voicemail. Embedded in laptops and fones, video cameras are becoming ubiquitous. Web browsers with Flash(tm) easily capture video from any device, letting web developers "just embed it." Now just add broadband internet/3G and season to taste.
Seesmic is structured as a forum for *discussion* rather than broadcast, and it's fascinating. Watch someone's comment in video, then watch others' video replies to it, then click to add your own video to the fray. The interface makes it simple to view the current threads or quickly find replies to your own comments.
I think this site's gonna succeed where others fail because it's not just another broadcasting tool ... it's about conversation. It'll be awesome to see what happens as the community gets bigger and integrates disparate voices and sub-cultures. The video flame wars should be spectacular!