I've noted, over the years, many sites that scrape craigslist data for one purpose or another. They run for a few months, get popular, get noticed by craigslist, get shut down.
Do you have ongoing communications with them to avoid this fate?
Do you have ongoing communications with them to avoid this fate?
u) use automated means, including spiders, robots, crawlers, data mining tools, or the like to download data from the Service - unless expressly permitted by craigslist;
If you are serious about this site and you think that it could become a largish site you should definitely get permission.
They also disabled Jeff Atwood's multi-city search: http://www.codinghorror.com/craigslist/ (he posted the letter he got from them)
Then again, http://www.housingmaps.com/ is still functional, and might be the most popular Craigslist mashup -- I'm assuming they have a deal in place with CL.