How much of your community growth is driven by referrals (word-of-mouth)?
How many members visit from links to discussions shared via members on Facebook, Twitter, Quora, LinkedIn and other platforms?
How much growth comes via pages you've set up especially for referrals?
The growth of successful communities is driven by referrals from existing members. Once you've past the inception phase of the community lifecycle, you need to move beyond direct growth (you inviting people) and encourage referrals/WOM growth (members inviting each other).
If this doesn't happen, your community is forever trapped in limited growth. Eventually this direct growth wont be enough to replace departing members. The community will lose momentum and enter a death spiral.
For many communities, especially branded ones, this doesn't happen. There are several reasons for this:
There are a few reasons:
1) Members have no-one to invite. There aren't any existing connections between the target audience. i.e. If I'm the only Ukulele player in a tiny village, I might not know any other Ukulele players to invite. For brands, this is especially true. For most community sectors, this is rare. It means slow growth and the ultimate emphasis on retention.
2) Members have no reason to invite anyone. Members have no trigger to invite others. You need to have a referral strategy to initiate that trigger. Don't leave this to chance. You also need to ensure that there is a culture of sharing discussions/posts within the community via social media platforms.
3) Lack of community spirit. Members haven't been around for long enough to develop a community spirit (see, don't ask referrals from newcomers), or there isn't a strong enough culture to make members want to see the community succeed. Embrace sense of community elements, ask for referrals from your most active members and work to retain and increase the involvement of your long-time members.
Referrals (or word of mouth) is the ultimate driver of successful communities over the long term. Without referrals, your community will struggle to survive over the long term. Carefully plan your referral strategy once your community hits critical mass.