Craigslist hates VoIP

Not sure how I missed this, I like to think of myself as being on top of the industry but I just came across this over the weekend.

Craigslist.org, the popular free classified ad site, has been at war with spammers for some time. According to some reports, 90+% of ads in some categories are generated by spambots. Craigslist has deployed countermeasures including CAPTCHA and other techniques, but spammers have quickly evolved their techniques to sidestep them.

A few months back, Craiglist instituted a telephone verification process that places an automated outbound call to a user placing a classified ad in certain categories. The call delivers a unique code using text to speech, which is then used by the poster to authenticate the ad they are placing.

This is an effective measure for dealing with spam, and a great thing for legitimizing the Craigslist user experience….but not so great if you are a Craigslist user and you also happen to be a VoIP or prepaid cellular user.

The problem is that Craigslist is categorically blocking legitimate VoIP and Pre-paid cellular users from authenticating themselves.

The phone verification process is fairly straight forward. When you place an ad in many categories on Craigslist, you are presented with the form below.

Craigslist blocks most VoIP phone numbers, including those from services like Grand Central and Tossable Digits. This is an apparent broad stroke to counter the use of such services by spammers to game Craigslist’s voice verification.

Craig’s uses a 3rd party service, ReduceFraud.com to screen out VoIP and Pre-paid cellular numbers, and will not deliver an automated verification call to a number that is determined to be such. (Since only SPAMMERS use VoIP and Pre-Paid Cellular!!!) What sophisticated algorithm does ReduceFraud.com use to identify VoIP numbers, you ask? They check the DID number to see who owns the NPA NXX X number block, and if the DID number is owned by Level 3 Communications, they classify it as VoIP of course. Whizbang!

Coincidentally, ReduceFraud.com is owned and operated by a CA firm called Telecentrex, who offers their own hosted VoIP service.

Amazingly, this has created a business opportunity for resourceful entrepreneurs. Literally dozens of services have popped up offering everything from VoIP DID Numbers that Craigslist classifies as Fixed Lines, to pre-authenticated Craigslist user accounts, to full-blown Craigslist Super Spammer Software Packages.

I even found programming requsts on e-Lance, Rentacoder and GetaFreeLanceer.com
offering to pay for workarounds.

I would love to find out which service provider Craigslist is using to delivery their automated outbound verification calls. It would be cost-prohibitive to incure circuit-switched LD charges to deliver all those millions of calls…..VoIPMonitor estimated nearly 24 million VoIP users by 2008 (i.e 24 Million frustrated, would-be Craigslist users)…..I would not be surprised to learn that the provider was leveraging VoIP to send these very same outbound verification calls. Now wouldn’t that be ironic?

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