Who Will Own the Code?
If you will allow community members to contribute code, will they be required to assign the copyright for their contributed code to you or to your company, or whether they will be permitted to retain copyright on their section of code? This may have an impact on the choice of license. Requiring copyright assignment will enable long-term control over the entire code base. This could be beneficial, especially if you want to use a dual license as described later.
Some community members may balk at the idea of assigning their copyright to an organization, even if the code is freely licensed as part of a larger project. This decision will be informed by your ultimate objectives with the open source release of your code. If objectives only include transparency and/or to retain ultimate control over the entire code, then copyright assignment is appropriate, but you may never see outside contributions. If you are seeking community involvement, then more thought needs to go into this decision, and you probably want to consider creating a contributor license agreement (CLA) like the one used by The Apache Software Foundation, which you can read at www.apache.org/licenses/icla.txt. Whether you decide to require copyright assignment or not, this will help you clearly communicate and legally define for both parties what is permitted and required.