Which open-source license should I use for my project?

I'm actually speaking to a group of University students about this very topic later this week.

In my opinion, permissive licenses such as MIT, BSD, and Apache are best for libraries. A library is not the final product, but is a helpful tool that could be of benefit to many different projects. It can encourage participation for many different sources, including commercial.

A copyleft license, such as anything in the GPL family, is better for a final product in order to keep people from copying the product wholesale and passing it off as their own work. The AGPL is probably the strictest license possible in this domain. A copy left license discourages commercial participation in many circumstances, although not all. The Linux kernel, for example, is GPL version 2, but does benefit from commercial contribution.

For philosophical reasons, some people will say that you should only ever use a copyleft license, regardless of the subject matter. They do this because they believe that everything should be copyleft, and copyleft licenses are infectious. That is, the inclusion of a copyleft piece of code forces all of the code to be copyleft and subject to the distribution requirements. It may also invalidate software patents which, again, some people are strictly opposed to, and therefore they will only recommend copyleft licenses.

There's a lot of nuances to the different licenses, and the license is often reflect philosophical and political beliefs. For me, personally, I have released my code as MIT, which I greatly favor, however I have also written gpl'd libraries for something like drupal because that was the only option as Drupal itself was gpl.

>> I'd also like to make money from it somehow.

As a general rule, you can assume that if you Open Source it you will never see any money from it. Perhaps beer money here or there but you won't be quiting your day job.

There are exceptions to this rule but they are exceptions. If you figure out how to get Open Source paid for, that will be more valuable than ERP.

ERP systems are also a terrible idea for Open Source. Your target market is Enterprise (the clue is right there in the name.) Selling to enterprise is a long, complicated, expensive cycle. ERP is at the very extreme of that cycle. ERP projects cost millions to implement, require integrations with hundreds, or thousands, of existing in-house projects, and have full time implementation and maintainence staff.

I strongly recommend you find a single enterprise that is even a little bit interested in talking to you before you go down this road (hint: you wont).

They absolutely do not download and try out ERP level software - that's just not how it works.

I say this not to discourage you. Building something can be it's own reward. But I just want you to be clear on your goals. The odds of anyone ever using this are very very slim. The odds of you making any money at all is near zero as makes no difference.

I'm glad though that you are thinking about the license. Its important to choose a license that matches your goals.

You going to be upset if someone else makes a fork and charges for use of it? You want that not to happen, or to have you name on it when it does, or to have a share of any money?

I think we need to know more about your goals, what you want to achieve here.

If its just fill your own need, and let the rest of the world use that and maybe even build on it, but you dont really give a shit once your happy, then MIT would be a great choice.

If you're concerned with how people use your code then you probably want something more restrictive.