We've thought about this a lot. There were some unique factors at play in Davis. One big one that we've really tried to fix with localwiki is that you had to be a pretty technical person to contribute to the project. Davis is, second to Cambridge, the most educated city in the US.
So making the most -absurdly- usable software possible was a huge priority. If you look around, there's really no easy to use open-source wiki software, so we had to do a -lot- of gruntwork. We wanted to, at the very least, remove the technically-savvy barrier.
And the standard for online collaboration hsa also risen quite a bit, but open-source wiki software hasn't kept up. Back when DavisWiki started, the very -idea- of web based collaboration was foreign. Nowdays, my mom uses Google Docs!