Confusingly many open licenses are available. A key issue for academics is to ensure the widest possible reuse of the material by setting minimal restrictions on the end user. I collected an Open Licensing Memo to help newcomers with selecting a license for scientific software, data and documents.
In summary, the FreeBSD and MIT software licenses are recommended since they set minimal restrictions on the end user, promoting the core scientific standards of publicity, transparency and unrestricted reuse. The popular but more restrictive viral GPL licenses are for the same reason less preferable in the academia, unless licensing compatibility issues mandate their use.
Open licensing can help to guarantee your own rights to your work, encourage reuse in a legally sustainable manner and have advertisement value towards funding organisations, other scientists, fellow geeks, and laymen. It is really simple, and widely encouraged.
Unrestricted reuse of research results is a cornerstone of science. Explicit policies – in part enforced by the open licenses – are needed to realize the long-standing scientific standards in the evolving publication landscape where an increasing proportion of research details are embedded in code and data accompanying traditional publications. Research institutions should grant explicit rights for the researchers to publish their code under an open license to promote transparency and reproducibility. At the moment, the legal status is often unclear in this regard, although many research continue publishing their code under open licenses.