For an online community to work, you need members participating. The number of members required depends on your community model.

In an interview for our book, Debi Kleiman from Communispace, a company that builds and manages private customer communities for over 100 brands, said that they’d found 300-500 members to be the optimal size for communities aimed specifically at gathering customer insights. Such communities normally depend on a high degree of interaction between members and the sponsoring company, and limiting the size allows for greater intimacy.

However, for most community models, a much larger population is required. Keep in mind that only a small percentage of members are likely to participate actively. The Spanish community 11870.com told me they had found that 5-10 percent of their members were contributing 90% of the content. Applying this rule, if you have 300 members in your community, you’re looking at 15-30 active contributors. With 15-30 active contributors, it will be very hard to keep the community sufficiently dynamic to hold members’interest. When members log on, they are likely to find that not much has changed since their last visit and that they are practically alone on the platform. This significantly reduces the chances that they will log on again. In other words, if you don’t achieve a large enough base population, the natural tendency may be for your community to shrink rather than to grow.

Size also has obvious advantages if your business goals for the community include any of the following:

  • Search engine optimization
  • Content generation
  • Generation of ad revenue
  • Viral marketing
  • PR benefits
  • Increased traffic on your e-commerce site

I’ll post here soon about some ways to recruit members to a community.