Harassment, publication of personal information
If your personal information has been posted on craigslist:
If you receive an abusive email reply to your posting with an address that ends with reply.craigslist.org, for example:
locate and use the last link that appears at the bottom part of that message:
"Please flag unwanted messages (spam, scam, other):"
If you are receiving email directly from another individual (i.e. you can see the sender's email address), it may be advisable to forward details of the messages, including the full email headers, to the sender's email account provider. If you feel the harassment is significant enough, it may make sense to report the issue to law enforcement as well. In addition, it may help to set up a block against the sender's email address in your email client.
You can flag abusive postings using the flagging links provided.