Much has been said about open core, but with the OSI coming out squarely against it on the one hand, and Rackspace and NASA creating the OpenStack.org project as a "true open source replacement" for Eucalyptus on the other hand, it seems open core is now much less attractive than it was only a week ago. It seems everyone has now learned what open core is and agrees that it is not open source, nor is it good for open source. (And by "everyone" I mean everyone that really are open source advocates, naturally those who directly or indirectly are trying to profit from open core will continue to promote the model for a long time to come.)
The final question that remains to be answered is, if I know about open core and don't like it, what can I do to help prevent its spreading and rather promote the adoption of true open source?
With my personal experience working for MySQL, I've had a few years to collect some ideas, and would like to share them below. Please add your own in the comments and I'll keep updating this post so it can remain a useful reference.
(Last updated Aug 29, 2010.)