Why Can't I Reply to Craigslist Ads?

If you've created a Craigslist account and logged in to it, the site's ads include links that trigger popular email software and Web-based mail systems. On a computer that's configured with an email client program that launches automatically when you click on a "mail-to" link, the "Use Default Email" link in every Craigslist ad will open the application, create and address a message for your reply. To reply using the Web-based interface to Gmail, Yahoo, Hotmail, Live Mail or AOL Mail, use the individual links for these specific providers. If you can't or don't want to specify a default email client and don't use any of the Web-based services, Craigslist incorporates a link you can use to copy the ad posting's custom email address to the clipboard so you can paste it in to a message yourself. Finally, if you don't have or don't log in to a Craigslist account, you see a version of the ad that includes only a "mail-to" link that triggers your default email software. If you haven't established this default, the "mail-to" link prompts an error message.

When you craft a reply to a Craigslist ad but your email message to the ad poster bounces back to you as undeliverable, you may have responded to a posting that ended before you could send your message or that Craigslist removed for non-compliance with its Terms of Use. Craigslist structures its service as a community-monitored marketplace in which all users have the ability to flag ads that violate guidelines against spamming, advertising prohibited or illegal goods, and posting ads in the wrong or too many places. A substantial number of flaggings prompts a review and, if the ad really fails to meet the Terms, a removal. In addition to community monitoring, Craigslist uses automated algorithms to scan postings for other violations and remove improper ads without community intervention.

Almost every Craigslist ad uses its own customized email address for responses from interested parties. Craigslist creates this address when the person who posts the ad uses the Anonymize feature presented in the ad-creation interface. Anonymized addresses contain seemingly random combinations of letters, numbers and punctuation, making them all but impossible to type correctly. If you make a mistake in the address field of an email message when you reply to a Craigslist poster, your message will bounce. To make the process as easy and trouble-free as possible, always use the automatic emailing links or copy the address to your computer clipboard and paste it into a message.

Craigslist allows attachments to the messages you send to ad-specific email addresses, but the service places a limit on the size of the files you can transmit. Regardless of whether you attach bitmapped images, PDF files, ZIP archives or any other form of digital document, you're limited to a total of 25MB or your message will bounce back as undeliverable. To verify that your message meets these requirements, save it as a draft and check its size in your email client software before you send it. Simply checking the size of your attachments in a file window won't tell you how big they become as email attachments.