What makes people want to join an online community?

I wonder what are the factors and incentives that drive people to join an online community, and why not? My work normally involves different communities or evolves around these, but it is often difficult to anticipate how a community develops. Some things work, others not at all. To get a community started has a lot to do with experimenting. The other day I had an interesting chat with Nancy White and Joitske Hulsebosch about this specific topic, and decided to bring it up in public.

There are so many different ways to join a community. Some more or less binding:

• Mailing list
• Facebook Fan page
• Follower a Twitter member
• Register at a community platform
• Join a group (e.g. Linkedin)
• many more

What are the incentives and factors that make us want to join a community or social network?

• Reflects my topic or my passion?
• Affiliaton to the person or organization behind the network?
• The community is good facilitated?
• The organization behind it is trusted?
• It is dynamic and has a lot of exchange?
• Chances are high you get a feedback on a contribution?
• A lot of high quality content?
• Many / Few members?
• Public or closed communication or both?
• Some members are well known or famous?
• Friends are already members?
• Personal recommendation by a friend?
• It is advertised or branded?
• It has a great design?
• I find my way around easily?
• It has many funky features?
• It offers many ways to participate?
• It offers many ways to digest information?
• It is email based?
• Privacy is provided?
• You can leave the community easily?
• ...

What did I miss?

Of course, mostly it depends on the context and on the person, as Nancy remarked. It is almost impossible to generalize here, but it seems that there are a multiple of factors that count. But the multitude of networks are all trying to gain one's attention.

Lastly, this topic is also interesting as we often know so little about the majority of lurkers once they have joined and why they did? Ton Zijlstra and Lilia Efimova have some interesting thoughts about the value of lurkers:

"Lurking, although the word seems to imply a negative connotation, has usefull aspects nonetheless. It is a way of determining rules of behaviour for new comers to a group. (...) The most obvious characteristic of a lurker is that he is at the fringe of a group, listening and observing. Being at the fringe may seem like a bad place from the core, but in fact is a good position to build bridges to other groups, and be aware of other groups in the vicinity. "