I run HelloBox - http://www.hellobox.co http://www.hellobox.co - a tool to create and manage online communities. One of the main things that we encourage commu

I run HelloBox - http://www.hellobox.co http://www.hellobox.co - a tool to create and manage online communities. One of the main things that we encourage community owners to do is to let their community grow organically. This means, implementing features where sharing is easy, inviting other members are easy, email notifications etc. It's been really helpful to watch the communities grow this way. Hope that helps.