DataPortability Video is Place to Start Understanding
Marchall Kirkpatrick at ReadWriteWeb has posted a good background about New Video Explains the Basics of Data Portability. The DataPortability - Connect, Control, Share, Remix video is under 2 minutes in length and explains the reasons why the DataPoratbility.org group is important. It aims to ease the pain many are experiencing as they use more social media, social web services, social networks, and/or social computing services in their personal and work life.
Control
The biggest piece in this for me is control with translates to services respecting privacy wishes among other desires around trust and control of sharing. As Tom Raftery points out With the rising interest in, and use of Social Networks (FaceBook, Plaxo et al) there is growing unease in what those sites are doing with your data, never mind the inconvenience of uploading all your data every time you join a new site. The DataPortability.org aims to include in its focus data that is "shared between our chosen (and trusted) tools and vendors".
I have been working around the edges on a project whose aim is to respect these privacy wishes. This is one of the things that really needs to be at the core of all services entering into this market segment.