The producing open-source software book is a gold mine of information on starting open-source projects. Yet I am hoping to learn more from the experience of stackoverflow users and was wondering what are the mistakes you made when starting a new open-source project (or difficulties you encountered when attempting to contribute to a new project), and how would you avoid these traps to become a successful project*?
**Successful loosely defined as a project that is used, and attracts active contributors.*
Choosing the wrong license (for different values of ‘wrong’) is a common pitfall. Two examples:
1.) If you’re using a license that does not allow for relicensing under different terms and you accept contributors code, you need to keep in mind that the code suddenly is not yours anymore. This is fine for some hobby project, but might limit your commercial options later. Of course, it also limits other’s commercial options too.
An example for this is the GPL. Include contributed code under this license and you’re bound to the GPL yourself and can’t decide to dual-license later (unless you nail this down for every contributor). Even a simple change of the license to a similar OpenSource license is impossible: See the linux kernel – it’s bound to GPL V2 and can’t be updated to GPL V3.
2.) If you’re using a permissive license (e. g. Apache, MIT, BSD) you need to keep in mind that not only you can go commercial and close the code later, but anybody else can do so too.
Don’t get me wrong: I like the GPL, I’m happily contributing to GPL projects and am glad that these projects exist. I also like BSD, Apache, MIT (the permissive ones) and am contributing to projects that others exploit commercially, e.g. through “Enterprise Editions” of the software that I’m getting OpenSource. It’s all fair game – you just have to be sure what options you want to have later. None is better, they’re just different.