While the ads that are placed in CraigsList are indexed and show up in organic search results vary fast, they also expire very fast as craigslist deletes them to prevent people from doing this, links expire within two days from google. I have had ads that I place show up in google within 12 hours of being placed but they normally only last for about 48 hours before being deleted by craigslist.

What Does This Mean?
Well simply you will have to keep reposting your ads every 48 hours. Craigslist has a 3 ad post limit in 48 hours.

How Do I work Around This?
I create multiple free email account at like yahoo or hotmail and then create numerous craigslist accounts with these email addresses. I then normally re-post my highest converting ads every 48 hours.

While you will have to re-post your ads to maintain top placement under your keyword, with a potential like I have done in the past to get 400 clicks to a affiliate products of yours over the course of a couple days FOR FREE is well worth it.