To find our current apartment in NYC, I just used IFTTT, plugging in the URL of a custom search (neighborhood, price, bedrooms, etc) on craigslist. Worked a treat
First thing I did was search for IFTTT references in this thread. :) I did the same thing in the Bay Area, and it worked pretty well. I should have made the filtering a little more restrictive though because I ended up with something like 5k emails/listings in 4 weeks.
There's a "Posted Today" filter on Craigslist that I used. That helps with old ads, but not continuously reposted ads though, which was still a problem.