Tracking links are unique URLs for your job's online application that can be pasted on an external job board or as part of the marketing of the job. When candidates apply through a tracking link, they'll be tagged with a pre-determined source and credit.
At this time, tracking links and job post links don't work on Craigslist. This is due to the fact that Craigslist blocks all tracking links to prevent spam, including from applicant tracking systems (ATS) like Greenhouse Recruiting.
In order to track any candidates who learn about a job in your organization from Craigslist, create a custom application question such as: How did you hear about this job? and include Craigslist as an available option.