If you want to buy a sofa within a ten-mile radius this site might not do you much good. But if you use Craigslist to look for trends, the way people are using search words, standard ads across several markets, or you’re looking for things regionally, you’ll like http://www.allofcraigs.com/.
The site is just what it sounds like: the home page allows you to enter a query, specify all Craigslist (or all Kijiji or all a couple of other ad sites) and get a list of search results pulled from a custom Google search. I did a search for blender and from the front page got results from a variety of places including Boston, Miami, and San Francisco. There was enough of a snippet of information in the search result that I could get both an idea of when the ad was posted and what was being offered.
What I did NOT get was a results count. What I DID get was a set of labels at the top of the results that had tagged the results by geographic area. Tags included Texas, Northeast, Florida, Southeast, etc. So though I could search all of Craigslist with the engine I could also just as easily narrow down my search by geographic area. Now if this search result also provided an RSS feed, like a regular one-market search of Craiglist does, it’d be just about perfect.
As long as you’re here, check out the Twitter stream tool that allows you to see tweets that contain the word Craiglist. (I think I would have filtered these to show only those tweets with links, so you don’t get random tweets like “I’m trying to find a couch on Craigslist.” Most of the ones I saw did have links, though.) There’s also a widget for allcraigslist.com that allows you to embed the search.
As I noted in the second paragraph, allcraigslist.com is built on a Google custom search engine, which means that it’s as good as Google’s indexing. I don’t know if all Craigslist properties are getting 100% coverage, but I do know that each of the test searches I ran got several pages of results from several different Craigslists. Worth a look.