I had the good fortune to talk about Arborwiki and Localwiki at eChicago in April 2013. Here are the notes that I took in preparation for the talk; the actual text of the talk varied from this, since I was speaking impromptu.
Who: More than a dozen core contributors over the lifespan of the project, plus many more who have made small edits to pages.
Where: Greater Ann Arbor - including Washtenaw County and the farmers who come to the Farmers Market from surrounding counties.
When: Started in September 2005 as a class project at Community High School, then moved to servers at the Ann Arbor District Library.
Why: To build community information about the Ann Arbor area.
Locality, not notability, is the main criterion for relevance; if it's here, then it's relevant.
Take a local point of view, not a neutral point of view; original text and personal views welcomed.
Lots of external links to reference sources.
State of the project
Arborwiki is a mature system - it has over 10,000 pages in it, and thus there's likely to be something about most things that people might look for that are relevant to the Ann Arbor area.
One advantage to maturity is that a lot of people know about the project through a popular "Birthday Deals" page, and we don't have to explain in the abstract what we're working on - that individual page gets about two hundred visits per day.
A second advantage is that we've gotten tremendous amounts of cooperation from the Ann Arbor District Library system, including help with research, links, technical support, and free hosting for this community project.
Challenges of a mature system
There's no "new wiki" smell, and we can't count on having a barn-raising strategy for people who want to document their community for the first time. Any enthusiasm has to be in the context of a lot of things that already exist.
The core of regular contributors is relatively small compared to the number of pages in the system. It would take 30+ page edits per day of existing pages just to get enough eyes on the older parts of Arborwiki just to keep each page refreshed to be less than a year since its latest edit.
There are too many short, uninformative pages with just a single bare link and no photo, no map, no template etc. One editor - and that would be me - went through a long period of emphasizing quantity over quality. Now that the quantity is there, it's time to focus on quality.
The site needs more photos and better support from photographers.
The Ypsiwiki problem
Once upon a time there was a separate Ypsiwiki which covered Ypsilanti. It was decided to merge those pages in because there was too much project overlap and not quite enough of a critical mass to keep the two systems separate. The Arborwiki name was retained, and as a result, there's resistance overall from contributors from Ypsilanti to contribute to a project that's not theirs.
What to do next
Improve the most popular pages on the site. Use Google Analytics to identify the pages that get the most traffic, and go through them page by page to ensure that they are up to date, correct, accurate, and informative.
Create new pages based on a "Page not found" report from Google Analytics, noting where people click on terms that get them to a blank or empty page.
Visit a random page in the site and make it better. Add a map, a photograph, a category, or a paragraph of information.
Learn the seasonal rhythms of the site. For example, the Paczki page gets traffic for about a week a year, but the Donuts page gets steady traffic year round.
Follow public meetings like the meetings of the Ann Arbor City Council, and tweet out links to projects or issues that are relevant agenda items.
Wish someone a happy birthday by sending them a link to the Birthday Deals page on Facebook.
Reward new contributors by recognizing them in public through Facebook or Twitter links to their new contributions.
Recognize that a Localwiki project has a natural size, and identify where you are in the process.
Pay attention to traffic patterns - popular pages, referral sites, keywords used.
If you want traffic, track the news, and befriend local media so that they are aware of the resource.