Inside Craigslist's Increasingly Complicated Battle Against Spammers

John Nagle writes in with a fascinating dissection of the ongoing battle between Craigslist and spammers. The back-and-forth nature of this battle is fascinating–and somewhat disturbing when you realize the lengths to which spammers will go to get spam onto Craigslist, and the extent to which an entire ecosystem of scammers and software providers seems to have been built up around this effort:

“Spam on Craigslist has been a minor nuisance for years. Not any more. This year, the spammers started winning and are taking over Craigslist. Here’s how they did it. Craigslist tries to stop spamming by checking for duplicate submissions. They check for excessive posts from a single IP address. They require users to register with a valid email address. They added a CAPTCHA to stop automated posting tools. And users can flag postings they recognize as spam.

“Several commercial products are now available to overcome those little obstacles to bulk posting. A tool called CL Auto Posting Tool is one such product. It not only posts to Craigslist automatically, it has built-in strategies to overcome each Craigslist anti-spam mechanism.”

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