Open Source Software Licenses Popular for code sharing: MIT (permissive, allows commercial use), GPL (copyleft, derivative works must be open), Apache (includes patent protection). Creative Commons Licenses CC BY: Attribution required, otherwise free use CC BY-SA: Attribution + share-alike (derivatives must use same license) CC BY-ND: Attribution + no derivatives (no modifications) CC BY-NC: Attribution + non-commercial only When to Use Open Licensing Building reputation, creating learning resources, contributing to community, or dual-licensing (free personal use, paid commercial). Risks and Benefits Benefits: exposure, community building, portfolio building. Risks: loss of commercial opportunity, attribution may not always occur.