An interesting post by Anil Dash (via Tyler) about the evolving ability to deliver realtime messages to a large audience using an open-source (read non-proprietary) plaftorm that he's calling Pushbutton.
Currently, it's mostly an asynchronous Push-Pull model. I update my blog, and then if you subscribe to my RSS feed, you get an ALERT that I've updated, but not the message itself. You, as a user have to go and physically get the message (either manually or via a Social Networking platform such as Facebook or Twitter).
!n the Pushbutton model, it's Push - Push. "...it proactively delivers not just the notification that there's a new message but the content of the message itself." In other words, it saves the user a step in receiving information - and it happens in near realtime.
A cool concept based on existing and expanding technologies.