Open Source License

Client and server software will be available under an Open Source License. The only question is: which one? There are various possibilities with different implications.

Should it be "infected" by GPL? Pros: changes will be publicly available and it makes the use of GPL code for the project possible. On the other hand, most desired libraries are under LGPL and can be used unmodified anyway. Cons: commercial enterprises might refuse to invest in GPL code to protect their investments. We want commercial use as much as possible. But do we really want commercial applications, which do not feed back their changes?

Should it be under a "free to use" BSD license? Pros: anyone can use it without publishing changes. Commercial applications are possible without restrictions. Cons: we might not get improvements back. This also means that the commercially operated code is not under peer review and thus might be at risk.

What are the licenses of other infrastructure projects, like Apache? Is the Apache License GPL-alike or BSD-alike? The "Derivative Works" in Apache's section 2 sounds more like BSD. Big projects seem to have no problem omitting the "infectious" part of GPLv3 section 5c. For example Hadoop, developed commercially by Yahoo, contributed to the Apache foundation, and used heavily by other companies is under Apache License.

What is your favourite license?