Communities: One Size Fits All?

I read a great article, thanks to a twit by Cool Cat Teacher, about communities and social networking. It seems like a lot of people are using the buzz word "community" to try to pull people into their site. I know a few months ago I joined the American Idol community, the Oprah Community, Ellen's Community, and then a few others as well. Oh, and some food item community -I think it was Kraft -just so I could get the recipe.
The thing with each of those communities is that there was no desire to stay active. Okay, I take that back - I stayed active in the American Idol Community and was even the David Cook trivia person for the Tuesdays before each show in the David Cook forum, but since he's been crowned as our Idol, I haven't been back. And unless there is another idol of Cook's talents, I don't plan on logging back in. I only signed up for Ellen so I could keep up with the American Idol chatter. Oprah because there was a forum I was interested in, but that topic soon fizzled.
I have seen a few teacher communities with staying power. In the article, it was mentioned that a lot of "communities" are not true communities but rather end users and the problem with most "communities" is that they do not harness the passion or interest. Okay, I'll give him that. So what makes the community a true community?
One topic he brought to light was that those involved need to have a similar interest and a sense of shared experiences. So I go back to an education community that I joined over a year ago. I had an interest in their product. It was catchy to begin with. However, since it's inception I have not truly gone back to the "community" website because I did not share any experiences with the other members. The David Cook group all shared our anticipation up to the show on Tuesday nights, our prayers and wishes for David on Wednesday night, and then our joy when he won. Since then, the community has found another platform to share their experiences. The original community has fizzled.
So what can a community do to keep it from fizzling?
When I went back to the article I saw a response from Chris Abraham. I really like his quote: "What every successful community requires is community leadership. Community leadership can be organic and emergent or they can be hired in the form of online community managers or facilitators. A strong leadership — people who have skin in the game — is more important than a good web application; also, these community leaders are often the main draw to the community and can be the difference between keeping or losing your members when a competitor comes to town."
I can agree with that based on my experiences with the DEN. I was okay with it when it first got started, but once the leaders took their place, it became even more exciting. (Especially when I was a leader. ;-) ) I really believe the field managers make DEN the cohesive community it is today. Even when we lost the state/regional field managers, the leaders left -Lance, Steve, Scott, Betsy, Hall, Coni, and Jannita - really held the community together. The state leaders all stepped up and helped as well.
Some would say that the leader is not necessary when they refer to Twitter or even Second Life. However, those are loosely formed communities and someone always takes over to help organize the events. And in Second Life, there is a leader for those formally involved in the DEN, ISTE or other groups Second Life Experiences. There are also owners of the various islands who plan events. So again, a leader emerges.
So if anyone is thinking about creating a true community, they need to make sure that there is a central passion, opportunities to share experiences, and a leader with the same passion and goals of the members of the community.