Open Source Software Licencing for dummies/me:
1. Public Domain Licence: No restrictions, go for it.
Following are the Permissive licences from most open to most restricted:
2.1 MIT Licence: This is a common permissive (open-to-use) licence. Simple to understand, anyone can reuse and modify code, but the creator is not liable for any future use. MIT is almost identical to a 2.2 BSD licence. It is excellent as you can freely use it, and I would like to offer my code with MIT licencing.
2.3.GNU General Public Licence (GPL): This is a nice open-source licencing you can reuse or modify, but your work must be open-source and available to all. If you use GP, make source code available; anyone can use your derivative.
2.4 Apache and Apache 2: These are also Permissive but more protective than MIT licences.
3. Copyleft: This is more restrictive. Users can reuse, but any derivations are bound by the copyleft licence on the originals.
4. Proprietary: Most restricted, closed source; no change or redistribution is allowed.
