We want to open source our soon to be released SaaS platform (CMS), but we are having hard time to choose license that protects our intellectual rights and also gives rights for people to install it on their own infrastructure and host their sites there. Any advice will be appreciated.
If you don't want someone else to be able to build a competitor site, it sounds like you don't want an open-source license.<p>The best you can do with an open-source license is the AGPL, which will force any competitor site to release all of their modifications -- this means that they can't gain any advantage over you, because you'll have access to all of their code as soon as they deploy it.
What about the Affero GPL? It's a GPLv3 that also allow you to receive code modification when a software is used in SaaS mode.
I'm not sure if this is the level of protection you are searching, this has always seemed a bit to strict to me (as gplv3)...