I don't mind the scrutiny about where we are at; I am glad you voice your concern. That niggling feeling has been on a lot of people's minds. I hear them asking the 'after Twitter what?' questions. I am hearing another type of concern right now, with a small business helping I am helping out. It's a (yawn!) new media outfit but with a serious revenue model. To answer your question: what's the viability of the current business model of the companies providing social media services: Good, if you're prepared to zig while everyone's still zagging. Don't wait till these services change, plan for those radical changes. Some see speed breakers, others see course correction.