In: Computer Science
What does the term "Open Core" software mean?
Zimbra and SugarCRM are good examples of this. The idea here is, build an open source platform or product, and then have a more professional version of it which is not open source.
From Wikipedia:
Open core is a business model where an open source product is also made available commercially with additional features.
This requires the entity releasing the commercial version to have legal rights to do so, either from the use of an open source license allowing it, such as BSD, or the assignment of copyright from all software contributors to that commercial entity when using licenses such as the GPL.