The document discusses open source software licenses. It defines open source and compares it to public domain and freeware licenses. The main open source licenses discussed are the GNU General Public License (GPL) and Berkeley Software Distribution (BSD) license. The GPL requires derivatives to also use the GPL while the BSD allows derivatives to use other licenses. Pros of open source development cited include peer review, motivated community contributions, and avoidance of vendor lock-in. Potential cons include projects becoming niche or fragmented.