There is an emerging career path for facilitators of online communities. It is a unique set of skills requiring great sensitivity, patience, and grace. A key function of a facilitator is to model constructive online behaviour. Structure an online environment that will make it easy and efficient for people to give advice while also making it possible for them to control the amount of time they need to spend answering other peoples' questions. Online discussion on community issues works best in a limited number of situations.
Discussion is heavily moderated - even filtered to extract the most useful contributions.
Expect to follow-up through private email as well offline. Offline work is often a requirement for useful discussion. No need to take the time online or expose individuals to with individuals on a list offline - or privately through email rather than on the list as a whole. Develop a process to collect and showcase best community learning practices. Make sure that contributors get much welcome recognition for their innovation in developing those practices and that they are presented in a way that is replicable.