Nova Spivack, the wide-ranging thinker about matters Internet-ish, has an excellent post that categorizes the elements of the emerging "social operating system" on the web. Take a look:
In recent months we have witnessed a number of social networking sites begin to open up their platforms to outside developers. While this trend has been exhibited most prominently by Facebook, it is being embraced by all the leading social networking services, such as Plaxo, LinkedIn, Myspace and others. Along separate dimensions we also see a similar trend towards "platformization" in IM platforms such as Skype as well as B2B tools such as Salesforce.com.
If we zoom out and look at all this activity from a distance it appears that there is a race taking place to become "the social operating" system of the Web. A social operating system might be defined as a system that provides for systematic management and facilitation of human social relationships and interactions...
