Site permissions
Permissions management is one of the things that is typically different when working with community sites. Where a traditional department site is tied to a specific department and likely has an Active Directory security group, the community site is meant to be cross-functional including people from throughout the organization. Making that collaboration easy, especially for new members, often means taking a completely different approach.
The approach that I typically take is to identify the top most Active Directory groups that apply and then grant them Contributor permission level. That could be something like<my domain>\domain
users which is a standard security group that will include all domain users. Letting everyone contribute by default will make the site easier to maintain and also better support collaboration and innovation.