Why is Pentaho using the General Public License (GPL) for the Pentaho BI Platform?
The GPL is the most widely used open source software license. Currently, more than 60% of open source projects tracked on freshmeat.org are GPL-licensed. The GPL is well understood by the market and the legal community and has notable precedents such as MySQL, Java and the Linux kernel as GPL-licensed projects. Because the GPL is what’s known as a “reciprocal license” it ensures that the software is open and remains open.