Joel Spolsky writes about the need to look beyond the user interface and focus on designing the right social interface:
Software in the 1980s, when usability was “invented,” was all about computer-human interaction. A lot of software still is. But the Internet brings us a new kind of software: software that’s about human-human interaction.
Discussion groups. Social networking. Online classifieds. Oh, and, uh, email. It’s all software that mediates between people, not between the human and the computer.
When you’re writing software that mediates between people, after you get the usability right, you have to get the social interface right. And the social interface is more important. The best UI in the world won’t save software with an awkward social interface.