program such as StatusNet , a Twitter-likestatus-sharing system, and you deploy it and make some tweaks to the user interface and add a few features, anyone can download your modified version and run their own instance of it. Another example is ownCloud , which is offered as either AGPL or under a commercial license. For customers this does offer some interesting risk mitigation; if for whatever reason you no longer which to use your existing service provider, you have the capability to switch to an identical service run either in-house or by another provider, as the complete source code for running the service is available. However, for a service provider it may be less attractive, as you have limited ability to differentiate your offering in the service itself -- though you can still excel at customer service, reliability, pricing and other non-software services. Secret Sourcery However, while Kuhn, Moglen and others were developing the AGPL, an alternative model for open source was emerging, based on using liberal licenses such as MIT, BSD and ASL . In this model, while the core software used for offering the service is open source, some of the "glue" code that binds it together, and typically the user experience offered for the service, is closed source. For example, while most of the software used to run Github is open source, GitHub itself cannot be downloaded and run elsewhere as some of its code is closed source; a strategy that Tom Preston-Warner outlines in his post