I use craigslist often. I disagree that "community" is what makes it a popular site. More important in their success, in my opinion, is it's simple to use, the pages load fast and aren't bloated and it allows people to sell things quickly and easily for FREE. Plus, some dissatisfaction with eBay has also helped craigslist in the eyes of a number of people.
I've sold a number of things there and can't think of an example of the community being an asset. I can think of some examples of the community being a hindrance.