Norms and Rules in Online Communities

I've been spending a lot of time recently thinking about the governance of online communities. One helpful starting point for this is the Preece & Maloney-Krichmar definition of online communities:

The people who come together for a particular purpose, and who are guided by policies (including norms and rules) and supported by software

My thinking has always been that communities need to develop their own norms, and should enforce those themselves. Tools might be provided to help with this (possibly to a select number of moderators within the community), but the majority of the responsibility lies with the community itself.

In trying to grow some of the online communities I help facilitate, I realised it isn't quite as simple. Yes - tech that enforces hard rules (you can do X, you can't do Y) might actually serve a purpose in certain scenarios.

Especially at the early stages of a community (or a newly created sub-community), being prescriptive with rules and enforcing them from the top down might be a good practice, as self-enforcement and development of community norms can happen efficiently within a pre-defined framework than within a fully blank space.

I still feel however like software should not be the primary driver of any policies, but applied as a tool: the community needs to feel like they are in control for there to be an environment where collective norms can grow.