Confused about open source Dual-Licensing?

Recently a couple of analysts have shown confusion about dual-licensing of open source software.

A Matt Aslett (451 Group)  survey shows that he was asking which business model open source companies are using ‘open-core licensing strategy’, ‘single open source license’, or ‘dual-licensing’. This make it looks like dual-licensing is an alternative to the other options.

During Brian Prentice’s (Gartner)  session at OSBC last week he inter-changed the terms ‘open-core’ and ‘dual-licensing’ were the same thing.

In reality dual-licensing is not open-core or an alternative to it. Dual-licensing is the provision of the same software under two licenses, an open source one (usually GPL), and a commercial one. Dual-licensing can be applied to open source software regardless whether the company also offers proprietary software or not. So you can have an open-core model with or without dual-licensing. You can also have a pure-play open source model with or without dual-licensing.