"The term "open core" essentially means that the heart of a
software project is built on, and remains, open source but added
features may not be (particularly a commercial version intended for
enterprise use).VC-funded software startups love this model.
"There's a lot of controversy about it -- and not all of it from
FOSS purist types. Some say it's the best of both worlds, giving
software companies access to committers, giving users the ability
to make changes, while hiding the parts that could be valuable
intellectual property, and making the software company responsible
for them. Others say that it is nothing of the kind ... just a
variation on the classic software pricing game that gives user a
free taste with the goal to up-sell them to a proprietary full
"Most people involved in the open source movement are generally
ok with open-core in principal -- because they are generally ok
with any license in principal."