How do you build communities on line?

I don't really belong to any on line communities. So I started this week's assignment blog with the question posed above. And found a wonderful site that talks about it. Here is a clip from her webpage - 

Conclusion: what makes a successful online community? A single, easy-to-use feature. Click here to participate. Do only this one thing. After you get your participants “addicted,” go ahead and add another thing. Most of us are too busy to learn how to use all the features of a full-featured online community. 

That line totally speaks to me. She lists some sites that are trying to build communities, as well. 

If you'd like to read more about her approach - click on this link.

Another site I found talks about the tools one can use to build a community. From that post I cut and pasted this: 

How do you add community?

There is no tried and true method to encourage community spirit and feeling on the Web, but there are some tools to help encourage community.

Bulletin Boards and Online Forums
Bulletin boards are a great way to create an online community. Most forum software allows people to browse through the postings before logging in, and once they feel comfortable they can set up an alias and submit their own posts.

For example, my bulletin board allows you to read and post about HTML related topics. There are currently nearly 100 different topics, with many more responses and information.

This bulletin board uses Delphi forum software.

For more info from the "about.com" page - click here.

The above page says if you regularly visit a site you are in that "community". So on second thought, maybe I am a member of some on line communities and just didn't know it.