I missed my co-workers, but I didn't miss getting up so early! I'm getting jealous of the 4 day work week.
Now searching craigslist.org (CL) for housing or a car can be time consuming if you simply repeat the search over and over to find the newest posts. Also, it is not possible to directly search more than one region (i.e., search for a car in SF Bay Area, Sacramento, Modesto, and Monterey Bay). But there are several ways to get around these problems:
(1) CL offers RSS feeds - these are little subscriptions that can be sent to a simple program on your desktop which update like news headlines everytime a new result matching your search comes up.
(2) Crazedlist.org - searches multiple cities/regions at the same time and provides the results on a single page. It has a little bugginess for firefox users, but it's easy to work around.
(3) Craigshelper.com - very similar to crazed list but with ads for other services, forced to initially also get eBay results, promotes the author's other programs (which may be useful, such as Hankshelper.com which searches multiple car sale sites simultaneously).
(4) Craigspal.com - comes in a "free" (which is VERY limited) and "paid" version that will notify you by cell phone SMS or email. Can do multi-city searches. Requires a download though. Honestly, I wasn't too impressed.
(5) Craigslist Search - easy multi-city search, some minor bugginess with removing cities from results in tabbed view, but great interface/tabs compared with others.
There's no one solution to both (1) notify you of recent posts AND (2) search multiple cities
UNLESS you create your own RSS feeds for separate cities and searches.
Maybe these attempts will get somewhere or CL itself will make the feature available in their efforts to remain at the top as they get pressure from eBay, google, and others similar free classified sites. Hear that folks at 9th & Judah? Have a slice of Milano's or Arizmendi and think about it, eh?