How to measure community engagement and effectiveness?

The first thing (and in most cases the only thing) I tend to see on online communities is forums or discussion groups. Which has led me to really think about the question –

What are the key metrics to measure an engaged online community?
What do you really need to get a community to be vibrant,
thriving and engaged?

First lets draw some boundaries so this does not end up being a post about what a community is overall.

1. The question should not be to be looked at from the perspective of technology alone.
2. Discussing social needs or psychology of why people need to form communities or social networks is also not the subject of this discussion. Those are much deeper discussions.

So then what all do you need to ensure that your community is engaged? Here are some ideas:

1. An engaged community invites and encourages new members or converts to “get religion”. Measuring new members in a community will not tell you whether a community is engaged. There is a need to track referred community signups. The additional need is to figure a way to make sure offline (word of mouth mentions) referrals are also tracked.

2. Time to find information. I have seen metrics from several consulting organizations that talk in glowing terms about the “amount of time” spent in the community by its members. If the community’s objective is to find and support users quickly (for customer service communities) then the more time spent by members would indicate they are not getting what they want quickly?

3. Community Contribution Value: At the end of the day if one simply looks at revenue generated for a company or costs saved, then there is a need to track precisely how much in actual $ was generated or saved. This is the most tricky part that I have seen no company do so far. There is new research around this area that promises exciting ways and means to track it.