Governments have started opening data for many reasons: it is a politically positive action and it alleviates the responsibility of analyzing and interpreting the data internally. Social Networks open data so they can become more valuable as the hub of many spokes, since 3rd parties will develop applications that make their data more valuable. Will traditional businesses open their data? Are some forms of data such as financial data necessarily closed-off and high-priced?
One of the things I focused on in my remarks was that governments already publish a wealth of data; they just may not conceive of these efforts as a part of the “open data” movement. For example, New York City has spreadsheets of every building permit issued going back to 2003. It’s not a “data feed”, but it’s definitely useful. The nascent industry built around open government stands on the shoulders of these spreadsheet-makers.