As a recruiter, I can honestly say that persistence can pay off. There have been several occasions where a candidate I passed along didn't get rave reviews, only to get moved forward because they didn't totally bomb and then kept calling. Was the hiring manager head over heels in love with them? No. Did they get and then keep the job? Yes. Once you're in the door you have every opportunity to show that hiring manager up by just getting the work done. Just don't hassle them. If you get someone on the phone, keep it short: you're still very much interested in the position, haven't heard anything, does the person know anything new about where you stand? Call maybe twice a week (and no more than that) until you get a final answer.

EDIT: Also, reposting a position on Craiglist may simply mean they're hiring for multiple openings.