Community Standards

So that's a design principle: Differentiate between active members and passive members. Do you have other design principles?

A sense of history is vital for an online community, especially as it grows over time. But forgetfulness is part of history too. It's easy for a Web site to "recall" everything that's ever happened there, but what you end up with is a big mess. The important question for a community is: How do you remember what you need to remember in order to develop a shared history?

There are a few principles that apply here. You can allow members to delete things that they think are no longer relevant. You can have only the most recent posts appear on the site, or you can have events appear in reverse chronological order. You can also let members "age" things - by letting them specify that their posts should be deleted after six months, for example. While member-generated content should be eternal, individual transgressions should have a statute of limitations. Members should be able to redeem themselves: A successful community learns from its mistakes.

The flip side of history is what I call "expression." Every community has a shared sense of itself. But that doesn't matter much if members don't know what's going on. Members need to have an easy way to take the pulse of the community at a glance: What topics are under discussion? Which members are reaching their goals? Who's on the site now? How many people joined today? Who are the top 10 posters? Are we accomplishing what we're here to accomplish?

If you went to a PTA meeting, you'd never have any questions about what was going on. People would either be talking about a topic, or they wouldn't be talking about it. Online, the points of interest aren't as immediately obvious. So you need to tell the community, "Hey, everybody is talking about this."

Can community and commerce mix?

Communities need to provide a way for members to exchange things of value. On eBay, people come together to exchange collectibles. But the items of exchange don't need to be objects. Information, expertise, recommendations, and positive feedback work just as well. But community members must be able to say, "Okay, I'll do this for you if you'll do that for me." In that sense, there's no great philosophical divide between community and commerce.

Are there limits to growth? How big can a community get before it suffers?

Here's how I think about size: How many people are there for whom the shared purpose of a community is essential to their sense of identity?

A real community needs to be one of the five most important things in the lives of its members. That's a pretty serious limitation on size. Let's say that a person is a parent, has a profession, and pursues a hobby. That person probably has time for one other thing in his or her life. So any community must be able to attract a reasonable number of people for whom it can become that fifth thing. That number determines how large your community can grow.

Katharine Mieszkowski (km@salon.com), a former Fast Company senior writer, is a senior writer for Salon.com. Contact Cynthia Typaldos by email (ct@realcommunities.com) , or visit RealCommunities on the Web (www.realcommunities.com).

Sidebar: 12 Steps to Real Community

Cynthia Typaldos, president and CEO of RealCommunities, teaches people how to build online communities -- and sells them the software to make communities work. Her "12 Principles of Civilization" will help you find out whether your community is for real.

• Is there a necessary shared purpose that we accomplish together?
• Does each member have an identity? Can we tell who's who, even if members remain anonymous?
• Are we able to share information and ideas that fit our purpose?
• How can we build trust? What tells us that it's safe to deal with other people in the community?
• How do we form reputations? What lets us build status?
• Have we created ways to work together in small groups?
• Is our environment a shared space that is appropriate for our goals?
• Do we know who belongs in our community and who doesn't?
• What's our system of governance? How do we regulate behavior so that it supports our shared values?
• Is there a system of exchange that allows us to trade knowledge, support, goods, services, and ideas?
• Are we able to express our group identity in a timely way? Are we aware of what other members are doing right now?
• Do we have ways to review our history and to track our evolution -- and leave behind what's best forgotten?