Craigslist ads is an American classified ads based online platform where you can post your ads about housing, for sale, items wanted, services, community service, gigs, resume, and discussion forums. Craigslist automatically monitors the IP addresses of where posts originate, so if they notice that too many posts are coming from the same IP, then those listings will get flagged for removal. Craigslist does this to prevent one person from spamming their site with too many ads at once. Many car dealers at single locations only have one IP address to work with, so using the same IP address to post on Craigslist Ads is often the cause of flagged posts. To aggressively advertise on Craigslist, you will need use multiple unique IP addresses. You can do this manually, or make use of an automated Craigslist posting service to do it for you.