With Wiffiti, you have a screen. You can show that screen on the Wiffiti site, full screen on your computer, or embedded in any web page. You have a name - people text @name to your SMS address (a five-digit number) and their message gets broadcast to the screen. Several messages show at a time, floating around the screen, getting smaller as they age.
Try it here - send an SMS message to 25622. Start the message with @jules, then type your message. It'll show up right here :) This screen is live. [update: odd... publishing this post cut off a whole chunk of text after the embedded screen. More of the review & a bunch of screenshots showing usability problems are after the jump.][update 2: if you're looking at this post in a feed reader, you may not see the screen - click through to the actual blog to see it.]