[gsnedders]

I think it varies massively with what the open source project is and what the goals of the project are.

If you're implementing an open standard to try and encourage use of higher quality implementations of that standard, a permissive license is probably the right choice.

If you're creating an open-source clone of some software (be it the GNU OS or LibreOffice), a copyleft license makes far more sense—the fact it is open-source is the defining characteristic of your software.

[Sir_Substance]

>the fact it is open-source is the defining characteristic of your software.

That's a terrible thing to aim for with your project, because anyone else can duplicate your defining attribute with the mere choice of a license. Why not aim to make the defining attribute that it's the best?

[ArneBab]

You left out part of the sentence: “clone of some software”.

Freedom is a goal in itself, and “clone” defines how it’s the best: be directly usable to someone who knows the other software.