I have seen a number of incarnations when it comes to making public data available on the Internet, from startup implementations like earlier InfoChimps, U.S. Federal Government efforts like Dataa.gov, and Socrata. Recently, Andrew Nicklin (@technickle), the Director of Data Practices at the Center for Government Excellence at Johns Hopkins University pointed out a version I haven't come across yet, the public/private sector hybrid:

"Publicly-operated data markets. This is an extremely interesting approach, because it provides a few other benefits beyond making government data accessible. With this approach, a government offers a public data market as a platform on which it and third-parties make a variety of data available, some for free and some at a premium. Because they are operating it, the government gains the ability to apply taxes or fees to data-access transactions (and this could be through any or all of the models suggested above), but it also gets an opportunity to regulate the market itself by establishing ground rules to protect privacy, public interest, and so on. Smart Copenhagen appears to be moving in this direction, and Smart Dubai may evolve towards this as well. (These platforms also present the opportunity for revenue generation through advertising, even if it’s just advertising other datasets to their repeat customers.)"

You can see this in action at the City Data Exchange in Copenhagen, Denmark, where the city has partnered with the Hitachi Insight Group to provide a data marketplace where public and private sector data can coexist, and as Andrew suggests, even allow for fee-based access (key point). Providing us with an evolving definition of what data marketplaces can be. I've seen a lot of data marketplace come and go, and this model, with a realistic business model for both public and private sector partners, provides me with a little bit of hope for providing access to public data in a sustainable way.

I will be keeping an eye on the City Data Exchange, and look for other similar examples. All the city data portals I track on are either public sector or private sector--no hybrids. Also, in this paradigm, only the private sector data marketplaces allow for fee-based access. I'll be adding this concept to my monetization of public data using APIs research, and see if I can discover any other examples in the wild, and maybe influence new partnerships between public and private sector organizations like we are seeing in Copenhagen. I think it is something we should be exploring in a very open and observable way, learning what works, and what doesn't, so that other cities can begin to develop strategies for managing public data, and even generating much-needed revenue when it makes sense.