The Mozilla Story

In the late 1990s, Netscape was facing a serious problem. Its browser, the Netscape Communicator, was rapidly losing market share to Microsoft's Internet Explorer, and it was difficult for them to define a competitive business case to justify ongoing development and licensing of their proprietary browser. Rather than simply shut down development, however, Netscape decided to turn it into an open source project and to license their software to the public under an open source license. But which license?

Netscape resisted using an academic license because, in the company's opinion, such licenses don't go far enough to return certain modified code back to the community. (This history is discussed in much more detail at www.mozilla.org .) They realized that academic licenses allow "middlemen" to remove improvements from the free software commons ”and they didn't want that to happen.

They also resisted using the GPL for four important business and legal reasons. First, they believed that the GPL was incompatible with certain obligations they had under other licenses for software they had previously incorporated into their browser. Second, they weren't sure if the GPL was consistent with cryptographic code regulated by U.S. law. Third, they weren't sure what their reciprocity obligations would be under the GPL for other Netscape products (particularly servers), and they wanted to be sure that other software of theirs could remain proprietary. And fourth, they were concerned that other companies would decline their software if the GPL were used.

Netscape even considered using the LGPL because that license seemed to narrow the risk that software that merely interacted with their browser would come under the reciprocity provision. But it too was rejected.

A Netscape executive and attorney, Mitchell Baker, who understood both the structure of Netscape software and the legal requirements, wrote a new open source license to address these problems. The resulting Mozilla Public License (the MPL), has been the model for most of the important commercial open source licenses that followed. Next to the BSD and the GPL, the MPL is the most influential open source license. Baker went on to become the Chief Lizard Wrangler of the Mozilla open source project.

The MPL is a serious license. I will direct much less criticism to the structure and terms of the MPL in this book than to the other licenses I've already written about, because the MPL is a high-quality , professional legal accomplishment in a commercial setting.

One of the challenges to writing about licensing in a book not specifically written for licensing professionals is to make a very dull subject interesting. For those readers who are skilled computer programmers, compare my challenge to that of an engineer who wants to explain C++ programming or the TCP/IP stack to the public.

How do I explain an open source license like the MPL deeply enough to make my description accurate without quoting pages of legal provisions and explaining how courts will interpret them? The most recent version (1.1) of the MPL is copied in the Appendices. Obviously I don't have to reprint each section seriatim and translate it into colloquial English, nor parse each sentence so that you can recognize a derivative work or a collective work when you see it.

So instead what I will do is paint a broad picture. I'll describe how the MPL and similar licenses from many other commercial companies are structured. I'll highlight things you and your attorney should look for in such licenses when accepting software under them, and what you need to consider when you modify those licenses for use in distributing your own software.