Working under the assumption that the Mozilla folks know what their license means:
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The licensing schemes used for Mozilla code have always had two major features: They have required that people make source code available for modifications to Mozilla code, and they have allowed combining Mozilla code with proprietary code to create and distribute proprietary products. Anyone contributing code to the Mozilla project under the "standard" licenses (i.e., licenses using the NPL or MPL in some form) has in effect consented to their code being distributed under these general terms.
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This is from a FAQ describing the adoption of the GPL by the Mozilla project (actually they're adopting a triple-option licensing scheme but let's not get into that!). The ability to combine Mozilla code with proprietary code to build a proprietary (and closed source) product's a big difference, and was done due to the relationship with Netscape, i.e. the fact that Netscape was releasing its code as Open Source but already had contractual agreements which made adoption of the GPL impractical at the time.
<p>aD doesn't have this excuse :)
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Hope this helps ...
