License change

Let me note that this switch does not change anything for regular users, it change things only to those who would like to use activeCollab code to provide a web service.

GPL is really nice license because it enforces sharing. If you take the code and change it you can use that changes internally inside your company without ever releasing the changes. When you go public you need to share the code you modified. Pretty simple. If you still want to keep changes closed you can come with an agreement with copyright owner (usually it means paying for keeping the modified version closed when it is distributed). GPL works pretty well here - you contribute the code or you financially support the project.

There is one major problem - back in 1991 when GPL v2 has been written software was distributed on floppies and there was no web services. Today we have a Software as a Service type of distribution (web services like Basecamp, Flickr, GMail etc) where you don't actually get the code of application, but you use it and it is publicly available. That scenario is not covered with GPL v2 as a distribution so rules of GPL can not be applied. Someone can just take the source, make a set of modifications, run a service and project can't do anything about that - no code contribution, no money.

GPL v3 should fix this problem, but until then we have Honest Public License, thanks to people at Funambol. Read more about HPL here.

Bottom line: nothing has changed except that if you provide a web service to the public based on activeCollab you need to provide the full source and changes.